If you want to stay with 9mm and shoot Production - you just have to buy a DA Witness.
Shooting minor (9mm) in any other classification (Limited, L10, etc) means that every time
you miss the A zone (and hit the B, C or D zone) you lose points - simply because you're
not shooting "major" (a .40 or .45).
So, yes, if you want to shoot Limited, get the Witness (SA) in .40 caliber.
+1 on this one. I tried Limited minor for a while and the disadvantage isn't work it, unless you slow down a bit to make all "A" hits. if you slow down then you are sacrificing time and then you are at another disadvantage.