I had a bt 99 plus and I had to jack the comb up so high that the set screws dented the hollow tops of the aluminum posts. A LOT of my friends had the same problem--they are VERY hard to get to shoot high enough for most ppl who shoot a relatively high gun.
BT-100 32" Barrel - Rib is 5/8” high at receiver and tapers down to 3/8 high at muzzle.
BT-99 Plus 34" Barrel – Rib is 13/16 high at receiver and tapers down to 5/8" high at muzzle, my current setting. The 99 Plus has an adjustable rib and according to the manual can be adjusted for POI from 3" to 12" at 40yrds.