Off the top of my head, there are three things to control.
Powder burn rate. The recognized spread is nothing faster than IMR 3031 and nothing slower than IMR 4064.
IMR 4895 was the powder used in 60's NM ammunition. It was a very popular Garand powder, giga tons were used in WWII and afterward. However, if a powder gave the proper port pressure, breech pressure, and velocity, (which WC852 does), and was cheaper, than the military loaded the low cost propellant.
I have shot both IMR 4895 and IMR 4064 in my Garands, M1a's. It is a matter of faith
whether one is more accurate than the other. I like IMR 4895 because it throws better.
I shot two pounds of estate sale IMR 3031 in my M1a/bolt rifle. That powder functioned the M1a perfectly. Given the design similiarities, I would have no hesitation using IMR 3031 in a Garand.
The second thing is bullet weight. Nothing heavier than a 175 grain bullet. Yes 180's were used, and you can use heavier, but you really have to cut the charge to almost nothing or you will get too much gas at the operating rod.
And I think heavy bullets are still hard on the gun.
Lighter bullets, like 125's, shoot well in the Garand and with the proper powders, are not hard on the rifle.
The third thing is port pressure. No one I know has a port pressure device, so control pressure by staying within known GI velocities. Spec value is 2750 fps plus or minus 50 fps. If you shoot American 50's era GI ball, you will find 150 grain bullets go around 2650 fps. The difference is due to the measuring device and how test barrels were calibrated, and ammo accepted in the test barrel, versus velocities in a sloppy GI barrel.
Go with the sloppy GI barrel velocity. Keep your velocities around than 2700 fps with 150 grain bullets, and around 2650 fps with 168/175 bullets.