RE: back plate mount
Mr3Putt
The Jett and Nelson mounts will fit fine in the TT Pro .40. You cannot use them in the TT Pro .46 because the bottom of the piston will hit the mount before reaching BDC. The stock backplate on both the TT Pro .40 and .46 is relieved on the top. LCS Performance has some nice mounts that bolt on the back of the stock backplate that you can use on the .40 or .46.
By the way, what club are you flying out of in the Milwaukee area? There is a good group of guys racing with TT Pro .40s in Wisconsin and Illinois.