I'm using 4.0gr VV N320 with Xtreme plated and Berry's plated with a 180gr. Gives me about 740FPS on average (you only need to hit 695FPS to make PF in IDPA). That's out of a Glock 35 which is only a tad longer than your 5.25" (5.31").
As always, work up the load and use a chrono.
I am experimenting with 3.8gr VVn320 with coated (Bayou) bullets and they "feel" the same but I have not had the chance to chrono them yet. Just wanted to see if they would cycle. But the recoil impulse felt almost identical. 3.6gr felt softer, but again I don't have velocity data yet. Probably in a month I will get time to setup and test some new loads.
I used to have a guy load 180gr moly coated with 3.5gr of titegroup for me and they were a little hotter so they could cycle the gun with stock springs. That was before I started loading myself - I will have to see if I can find any of his old stuff in the safe and chrono it next time I have it setup. But for me, the smoke was a turn off. The coated stuff doesn't smoke so that is a plus. I'm still playing with it though.
thanks, that gives me a good on where to start.