Hi there. We must have meet somewhere in Europe perhaps as you know my second bike racing name.
Nick the Velo builder basically taught me his methodology. It critical to get the two hole sizes correct. One a firm fit on the wire cable and the second big enough to fully retain the turned back birdnested cable strands.
Nick uses a pair of fine needle nose pliers and turns every strand back on itself one by one carefully creating a ball of wire that fills the larger hole. He can take an hour or more to carefully do a brake cable nipple. Then clean everything in a flux. Then hold the nipple in a vice and pull down on the cable getting the strands perfectly bunched into the large hole in the nipple. Then use what we term silver solder. About 3 or 4 % silver content solder using a large soldering iron.
A cable made this way is 100 % reliable but of course still checked for every race meeting.
I have found commercially made throttle clutch and most critically a rear brake cable which had no birdsnesting of the wire whatsoever. I cannot name names because I simple don't remember the manufacturer. It was maybe 20 plus years ago now but I still will only do my own cables.
Doing a set of twin throttle and choke cables is very tedious but unfortunately still necessary in my experience. I still remember the look of misery on Nicks face as their very first Velo KTT came to a halt half way through its first race at the very first meeting. The nipple pulled off the commercial throttle cable.
For carbs the nipples in the slide are very small but provided you can get at least 2 or 3 stands reversed into the nipple a throttle cable will be strong enough plus your life doesn't depend on it anyway.
