I have only one recipe which matches yours, I have used my numbers from the Speer #14 manual;
Case - Any of your good used brass will do.
Bullet - 124g RN FMJ (Precision Delta)
Powder - Alliant - Power Pistol @ 6.2g
Powder range - 5.6g up to 6.4g (Speer)
Burn rate -#33 (hodgdon)
Bullet length OAL - 1.150"
Velocity - 1,201.6 fps my 5 shot average @ 73 degrees
Crimp - Light
Test Gun - Glock 17 w/4.49" Barrel
I have a Lee Classic Turret press with the "Pro" auto disc powder dispenser. The best I can tell you is - yes it is a pain in the A$# to work with when you test charges and the one that turns out to be the best is the one not given by those disks!
Power Pistol is a medium burning powder so I went along with the recommended OAL by Speer coupled with the longer barrel keeps the pressure down with decent velocity and better than average accuracy in my G17.
If you have a Chronograph this will help you answer future questions like the one you posed. If you do not have a Chrono, pick a velocity you wish to achieve, check Alliant's numbers given and that will give you a better look at where you can start and not to go above your mark.