I used the screw it came with. If you look at the pic you can see I tore up the screw head pretty bad. That screw was a pain to get out and I should have bought a few replacements. You can get them from Cz USA.
It think it was a 3mm setup, might have been 4mm. The cool thing about going this route is you can adjust the pad to the angle that works best for your thumb. You will need to loctite it in when you figure out where you want it.
It’s been a couple of months and so far so good. I used quite a bit of loctite and torqued it down pretty good. I got the pad from a friend who prefers the original shadow release on his s2.
A shadow 2 release doesn’t work because of the thumb pad, maybe a regular shadow release? I ended up cutting mine down, drilling/tapping, and installing a shadow 2 pad at an angle that felt more positive.
I contacted CZ-USA about the thumb rest few times in the past year and they told me there wasn't one. I'd be interested in seeing the rest from Sebo weapons, but I can't seem to find it.
I was about to give up on my 9.4gr of 3n38 load because of powder spillage and decided to try the spill stop and bearing kit. I've done 500 rounds since with only one spill. I might add one more spill stop to soften it up a bit more.
I did the same thing. Ba9.5 needed .5gr more than my N320 loads and had a bit more snap. The SD's were better than the N320/PV loads and also metered very well. It would probably be a better/cleaner replacement for people who like HP38/231.
I've set aside a few rounds with a couple different bullets to see if there is any growth and so far nothing. I use a U-die so the tension is bit better than the Dillon I was using.