Back when I was chemistry major, all the “pre-med” students wanted “chemistry for majors” on their applications to medical school. There were hundreds of the freshmen pre-med students and only 30 places in the chemistry for majors laboratory, so the pre-meds had to all be weeded out within the first week of the fall semester. The year I was there, this was done by giving a very long reading assignment on the fist day of class with the instruction to read very carefully as there would be an exam on the material at the next class.
The correct answer for that exam was to say that the chemistry text contained a serious error in its math; and was therefore wrong. “The book may be wrong" was the best lesson that I learned at the university. I remember this lesson when I look at books on knitting.
Cabled cast on is the standard way of starting a gansey. Every knitting book illustrates it showing it being done with two knitting needles. I looked at the pictures and I learned to do it. It is not hard. I used it for socks and hats and pattern swatches, but this is my first really tight gansey that I have done. Anyway, for some reason, I was having trouble getting a nice consistent, cast on. Part of it is that I hold these long needles at a different angle than I hold the shorter needles that I had used for the pattern swatches. I cast on and I ripped off.
The solution is to use a crochet hook. A correctly sized crochet hook is a faster, easier way to do a NICE cabled cast on to a long needle.