Checked the throttle cables? you might have frayed cable which is causing one side to hang up occasionally.
I go with the previous advice on setting- with the carbs off I set the butterflies one turn open, the mixture screws about 1/8 th turn less out than the book, and 1/16 ": free play in the throttle cables - if you can get someone else to turn the throttle you can synchronize them near enough by feel.
If everything is in good order this will be as good as you need, and if it doesnt work you have something wrong that should be found and fixed - no point in trying to adjust it out.
For fine tuning I use a colourtune plug , and I balance with a Synchrometer flow gauge, but that is just personal preference.
And I check the valves by feel on a hot running engine -----.
Adelaide Hills, Australia. 93 R100 GS, 77 R75/7 ,70 BSA B44VS, , 86 R80 G/S PD, 95 BMW Funduro F650 ST