There's some good info in
[dps Warrior] Hit is hugely overrated if you want to read more. It
appears that the consensus is that it is a 1 roll system, but I don't want to put words in mouths. Essentially, this is what the info in that thread says:
* There is 1 roll to determine if something is a hit, miss, crit, glance, etc.
* 1% crit has no effect on the miss %, but subtracts 1% from your chance to hit
* 1% hit has no effect on the crit %, but subtracts 1% from your chance to miss
Make sense? I think I have that correct. Assuming it is, the formula should be
(ChanceHit+Crit%*CritModifier)*ShotDamage = TotalDamageFromShot
where
ChanceHit = 1 - (ChanceMiss - %Hit) - Crit%
ShotDamage = whatever the shot damage formula is for the given shot
So your Hit% converts miss chances to hits, and crit% converts hit chances to crits. I believe this is correct, but again, math mistakes may have been made.