The fastest that I have ever knit a good weatherproof gansey is about 2-weeks. Two hundred years ago, a good professional knitter could knit a "good gansey" in a couple of days. From a young age they learned skills that had been developed over generations, and honed by a long professional training. Some master knitters thought it required years of practice to learn the plain knit stitch, and that an apprentice knitter should move on to other stitches only after the "knit stitch" had been perfected.
Those generations of skills have been lost, and I do not have the advantage of long professional training. Fussing around with only pointy needles for 15 years, and then taking 5 years work to out how to use blunt needles (pins, pricks) to knit better and faster has been a bitter dose of humility. I was always a quick study. I was the guy that could sit down with a technical paper and in a few days, find the errors in it. And, yet it took me years to understand the virtues of blunt needles slid or "popped" in and out of stitches, compared to pointy needles.
I fully believe that everything I have learned about knitting could be improved by a few generations of bright-eyed, nimble fingered knitters, working like demons, to knit silk hose for nobles and ganseys for loved sailors. None of this is likely to happen. Nobles no longer wear handknit silk hose and sailors no longer go aloft in foul weather - even in square rigged ships.
And, I knit to make good objects. Victorian ladies knit to demonstrate disposable leisure time, that they had beautiful hands, and to remind (rich) suitors of the virtue of their "busy fingers". Whenever I think about teaching knitting, I remember these reasons for some knitting. Demonstrating leisure, beauty, and busy fingers may be good reasons to knit - who am I to dispute Queen Victoria?
Queen Victoria did not approve of knitting sheaths in public. In fact, she did not approve of manual labor within her sight. Fireplaces were cleaned daily and silver was polished out of her sight. Her rich ladies in waiting did not work at their knitting, they knit slowly (Weldon Style is slow!) to prove they were at leisure, and used large, slow, elegant movements to show their beautiful hands and associated rings and other jewelry. Those were hands without the wear and tear of manual labor.
Fifty years ago, I learned a technique of knitting that was very similar to the technique of knitting described in Weldon's Practical Knitter, First Series. Weldon's praises German and Shetland knitting but does not discuss the faster continental style of knitting. Weldon's does not discuss the Shetland's use of knitting pouches. Weldon's does not discuss hundreds of years of use of knitting sheaths by professional knitters in Europe, or Great Britain including India and the factory run by the British Admiralty in China. Weldon's is a lie. The patterns in Weldon's are mostly good traditional knitting patterns as used by good professional knitters. Knitting was a common profession, and every community had people with good knitting skills that were willing to share those skills. Every community had people that could make good knitting needles. Every community had members that could make good knitting sheaths. Knitters with good skills and good tools could knit the patterns in Weldon's. A knitter using the techniques and tools illustrated and advocated in Weldon's would be utterly frustrated. Weldon's was a lie.
Nancy Bush's book, Knitting Vintage Socks, takes sock patterns from Weldon's and dumbs them down so they are much easier to knit. Then, she devotes much space on how to knit those much easier to knit patterns. Nancy Bush's patterns have 3 important advantages for the modern knitter: 1) they are easier and faster to knit; 2) the yarns are available in retail channels; and 3) the tools are readily available (even if Weldon did, not mention "Oh, by the way, you will need a knitting sheath for this pattern!"
The downside of Knitting Vintage Socks is that resulting objects are not as fine or durable as objects knit to the patterns in Weldon's. I think real, professional quality knit objects are worth substantial effort.
Knitting sheaths support many techniques. I have found several techniques, and become proficient in a few. The techniques I have become proficient in are somewhat specialized for gansey yarns and sock yarns. These objects tend to be too warm for modern centrally heated structures, including places like homes, shops, churches, automobiles, trains, and airplanes. The objects I make tend to be durable - they are not fashion - with such durability, they are worth some effort.
That brings us to back to Gladys Thompson's Sheringham ganseys. (I am somewhat obsessed with them these days and return to the topic frequently.) I have been knitting socks [swatches] from yarns that I think might be appropriate.. They are firm, worsted spun yarns. (Unlike anything I see in the retail market these days.) I am trying to make the perfect sock fabric that would make the perfect sweater fabric.
Knitting socks from these yarns is one thing - that is very doable. However, knitting a sweater is a larger project. Many modern knit sweater patterns call for about 40 stitches per square inch. The "ganseys" I knit have ~80 stitches per square inch. The various fabrics I am knitting from sock yarns have ~150 stitches per square inch. So, knitting a Sheringham gansey is like knitting 4 other sweaters - I know lots of people that knit more than 4 sweaters per year. My dentist was doing some work on an old fellow, and he felt so much better that his wife knit my dentist a sweater in a week as a thankyou gift.
Nevertheless, I am rethinking my knitting technique to facilitate fine knitting. The motions are smaller, and thus may be faster. The forces required in each stitch are smaller, again making it possible to knit faster. I am using less splitty yarns, making them easier to handle, and again allowing faster knitting. I do not find such yarns in retail channels. (This post is for spinners willing to spin firm, fine, worsted with high ply twist.)
I had always thought that the rules of the the various speed knitting competitions allowed knitting as fast as possible. Now, I think not. The results of modern speed knitting contests make the reports of the knitting speed achieved by the Terrible Knitters of the Dales seem like pure myth. Terrible Knitters of the Dales were knitting gloves from fine worsted spun yarns on fine needles using knitting sheaths. They worked outside modern speed knitting competition rules. Few modern knitters use knitting sheaths, and the speed knitting competition rules specify big needles and splitty yarns. Dear Hazel showed us the virtues of a supported working needle.
After 20 years of knitting including 15 years of using a knitting sheath, I finally understand why a knitting master would require his apprentices to spend years perfecting their "knit stitch" before allowing them to move on to work involving purl stitch. Knitting fast and fine is a matter of feel - the needle moves faster than you can see, and you can feel if the stitch was properly finished sooner than you can see if the stitch was well formed. And, when knitting fast, it is important know as soon as possible if there is fault in the knitting, so you can go back and fix it quickly. Unknitting fine knitting is a slow and tedious process. Knitting was perfected to go forward, not backward.
The fastest way I know to knit fine, firm, yarns is with blunt 1.5 mm spring steel needles and a knitting sheath. (Hand held blunt needles are worthless!) Knitting a block of knit stitches with blunt needles saves hours and hours. However, blunt needles are not useful in fixing knitting faults. I use fine pointed needles and a fine crochet hook to fix faults. Generally, I can feel a fault as it happens, then with a pointy needle and a crochet hook, the fault can be fixed in a few seconds. If I was using pointy needles, there would be more knitting faults, but I could fix each knitting fault in several seconds with the pointy knitting needles in my hands. Between the slower knitting of the pointy needles and the longer time to fix faults, the blunt needles allow a panel of fine knit stitches to be finished much faster. The downside to my approach is that I need to keep a 4" pointy, 1 mm needle and fine crochet hook handy - either on the window sill a few inches from my right hand or outside my breast pocket hanging from a magnet inside my breast pocket.
These days, my knitting costume often includes either bib overalls or my leather welding apron. They both have good breast pockets, and help support the leather belt that holds the knitting sheath at what ever height it is needed considering the length of the needles and style of knitting sheath.
I guess only old guys wear bib overalls. As an old guy, I have gotten pedantic. I use 12" by 1.5mm needles for socks, but for the fingers of gloves and thumbs of mittens I regress to 6" by 1.5 mm needles. As a pedantic, I now consider them 2 different knitting techniques using different needles and different knitting sheaths. That is, if we had a knitting co-operative with one person knitting the wrists and hands of the gloves and another knitting the fingers/thumb, I would consider them to be using different tools and techniques.
Visualize what you want to do, then conceptualize a set of training exercises to acquire the needed skills, and acquire tools needed. There will be an iteration of improving skills and the tools. This is speeded up by making your own tools. Some of the tools I make may be better than what I need, but I use the best tools available - anyway. My AddiTurbos have languished in storage for years and years, only coming out for the occasional test swatch - not even one full sock.