For what it' s worth (FWIW)

I don' t shoot IBO but I shoot a bunch of NFAA stuff - our targets are up to 50 yards and we can have up to 5 pins - so - if I take my MAX yardage & divide by the 5 pins I end up with a 7 yard gap - from 20 on out...

SO - I have my pins set at 20, 27, 34, 41, and 48. My personal yardage estimation & ability to ' hold on' at various ranges makes me much more accurate with this type of setup. Very rarely do we see targets set at 20/30/40/50 they are usually a bit more & a bit less - so having the pins a bit ' off' is good. When I have friends trying to hold a gap or shoot it high/low I' m right on - and if it is a ' gap' shot the gap is TIGHT so I can still be real darn accurate!!!

Good luck!