For those with stacking issues, I polished the sear to trigger interface, put 3000 grit on a flat glass table, and rubber the sear on it, it will make it a lot better. I know some people say dont touch the sear, but as long as you polish perfectly flat and dont change the interface angle it will be fine. The hammer also needs to be good, that is easier to just replace with a CGW unit, or even better the full pro kit. I also did a full polish on the trigger where it meets the bar, looks like a mirror.
Polishing the trigger bar will not mess with stacking but does get out some of the grit. What will help with some stacking is the trigger bar spring, polish where it meets the bar, and lube with moly grease. Also bending it slightly to reduce the pressure on the bar will further reduce friction, maybe take 1/3 of the distance out.
I literally had not shot a single round through the gun, i stripped it, polished, installed the pro kit, and then took it to the range. My wife has the exact same gun stock so it was a good comparison, my P-07 trigger now feels pretty much identical to a Shadow 2 in terms of stacking and grit (which is 0), but with slightly altered spring characteristics, the Shadow is maybe a little better, the P-07 is fore sure a little lighter, I think I would prefer a stronger power TRS.