I'd 2nd or 3rd ASP detents, fluted hammer and a freaked barrel as the ideal setup. I just put together a micro phantom with that setup and a wevo UC kit and with running the TPC about 2 1/2 turns in and using a .677 freak insert I can get 43 shots before they start dropping off (and even then I could push the 12g if I had to in an emergency). I didn't bother changing out for the red spring either. My spring setup is completely stock. I do run the dropout 12g changer though so that probably helps a bit as it's the most efficient valve setup.
On the ASP detents yea they position the ball in the same place every time. I also still use a detent ring just in case a ball gets past the ASP (which the odd one like 1 out of a whole bag can) and I find rather than matching my paint an underbore works best.