[BB427]

I am sure you will get alot of different input on this. This is what I do but most of my engines are for drag racing.

I hope this helps.

Top ring
Mild build = .004 X bore
Drag perf. = .0045 X bore
Nitrous = .008 X bore
Supercharged = .006 X bore

2nd ring
Mild build = .003 X bore
Drag perf. = .0035 X bore
Nitrous = .0065 X bore
Supercharged = .005 X bore