G'day Olev,
It's a mine field, get it wrong, boom. Phil Irving recommended 66%. I tried that and it was good at 5-6000 so over the next couple of rebuilds I increased it till it was good at 7+. The flywheel was also lightened a couple of Lb's. This was all when it was an A7 on meths at 13:1. I only raced in Div 2 (poor guys) and was the first across the line at the NSW Champs at the Creek in '96, '97.
Now it's an A10 it feels most comfortable at 6-6500 = 100 mph. At 3200 = 60 mph it's not too bad, numb hands after about 30-45 minutes. At 30 mph I don't know, not there long enough. At idle the rear guard is like a pogo stick!!!
Different frames and fixings make a difference to vibes, I think my alloy engine plates help, but my over the top head steady hinders.
Balancing all the other bits ( rockers, valve keepers, etc ) is also very important.
After 2 weeks of rain the sun came out today. Short ride into town to warm up then 120 on way home. FUNNNN.
Cheers