Titegroup with the 9mm

So, what's the smallest/lightest powder charge you have tried with Titegroup and either the 147 grain Subsonic bullet or the 125 grain HAP?

Please, let's try not to digress on this one; don't need comments about other powders or bullet types.

125 HAP, 1.095" OAL, 5" Kart barrel
TG 2.8 grains, 846 fps
TG 3.2 grains, 950 fps
accuracy was nothing special

Thanks, I've tried 2.8 with the HAP bullet. Range Officer with a KKM barrel. It shot okay. Was wondering if I could go to 2.5. It's for our indoor league at 25 yards.