I think if you were to video tape a good riders hands during a ride you would see 1-2-and even 4 fingers used depending on the speed,terrain and differing conditions.This is more of a natural thing as opposed to a disciplined thing.Its not something you force yourself to do.IMO
As far as lever position,that will be more determined by the stance and posture you use most often on the bike.Some guys ride in an aggressive weight centered,standing chin over the bar.Some guys will ride their 300 like a Barkolounger with a beer in their hand.And some in between those extremes.
Levers in a more level to downward position probably suits more aggressive riders that stand.When a rider is sitting he is usually more relaxed and riding a slower pace so positioning is less important.
Basicly we line the bark busters dead perpendicular straight ahead.That way when you tag something they will not give way either upwards or downwards.
And we adjust the levers down of center in reference to the bark busters.
Electrical tape was mentioned for wrapping bars under reservoirs-perch-throttle housing clamps,mirrors,kill switch-control switches whatever.
Youll find plumbers tape may work better for you there.
Removing clutch springs to lighten clutch pull??
Um no.That will lead to many problems.
Most of the bikes being discussed here are already hydraulic clutches.
As was mentioned earlier over gripping the bar as opposed to lower body control is the beginning of the end.
As far as logs goes?? Each log is different size.bark,no bark,dry,slick,rotten whatever.combine that with angle of attack and wether the log is below you or above you.Well you see what Im getting at "2 blip throttle technique"
kinda like pei mei's "five point palm exploding heart"technique.
I wouldn't get to worried about all that,practice, practice, practice.
If technical riding is your thing.If you love to ride tough technical terrain and punish your friends,or not be punished by them.Buy a trials bike to practice on.