Anyone have experience with custom sear from Magnum airpower for Crossman pistols???

I don't know what you mean by a two screw mod. Polishing the OEM sear and a lighter or adjustable spring will help. The original and that model from AOA will give a two stage pull. When they were available the original was much less expensive than that one from AOA.
From my bookmarks, @jkingrph

The 2 screw mod can also be a 3 screw mod.
I've only tried 2


 
I had looked a couple of days ago and they did not show one. I think that one has an aluminum body and then a hardened steel insert where it holds the hammer back, and the screw is for some kind of adjustment, exactly how I cannot remember, I did look at it year or so ago. The couple I used were the plane models, a little rough, but light stoneing on the hammer and trigger bearing surfaces gave very good triggers, on as good as my 1701p triggers but no adjustment. The 1701p is adjustable for two stages, again cannot remember exactly how, but there are two tiney allen screws reached via an access hole at the back of the trigger guard. I set mine and forgot about it.
Do you mean previous version didn't made from aluminum?
It really tempting. I want prod/1701p trigger group but super sear only $30.