I just picked up a new Versa Max Tactical and put in the TTI lifter just to try it out. I didn't have any issues loading or catching my thumb. The bolt was hanging up when it was fully retracted so that's another issue I'll be working on. The original lifter is being welded up and will replace the TTI when it's done. I just wanted to get shooting while the lifter was out, and it's been good so far.
I use FireClean on the pistons on my 930, 1100, SLP, and AR bolts. Helps condition the metal and put keeps a barrier between the carbon and steel. It's much easier cleaning, similar to Slip 2000.