So.....
I gave it a good try. Was able to fit the new S2 RRK disco to how I liked it, got the DA pull nice, almost no reset in SA, and got the DA break to drop where I wanted it to. But the SA is still too far back for me. It's a nice trigger, and firing dry the reach feels okay even though short. But as with many things, how something feels dry-firing may be very different live-fire.
With the pistol buried deep in my hand while firing, the trigger reach is just too short, almost past my first knuckle (I have relatively large hands, not meaty but longish fingers). This is with the original Shadow 2 trigger (which I believe is the CZ 'Shadowline' trigger), the CGW 'Old Style' 85C trigger that came with the RRK kit, and an extra 'Original' 85C trigger which is the thickest of the bunch. Even the latter was just a bit too short.

I think it has to do with the shape of the backstrap and its angled 'hump', as opposed to the more even arch like on the SP01/Shadow 1 and my Sigs.
So even though I was hoping to get my Shadow 2 back into USPSA Production (which is pretty much what the gun was designed for), I'm keeping it SAO. I just like the pistol better that way, I shoot it better that way, and I have a milled TS slide in .450 the can work on the S2 frame if I want to go Limited Major. So again, gave it the ol' college try, but I'm sticking with SAO.

So I'll be shooting my Shadow 1 in Production, which I've been shooting quite well with in IDPA. That gun is still more stable in DA, and the length of pull in SA is more to my liking.