rromano,Suggestions welcome!
M1s, like all rifles can be at least a hundred feet per second plus or minus any other Garand due to bore wear or lack of, exact bore diameter, etc. Function is dependent on gas cylinder diameter as well as the gas piston diameter, gas vent and overall wear of the gun's mechanism. Larger tolerances in your gas system will require more pressure and so on.
I load for four of them, and while they are usually within 50 fps of each other over the chronograph, they all have their idiosyncrasies.
As I posted earlier, I use a non canister powder that is in between 4895 and 4064 in its characteristics. 36 grains is the sweet spot for this powder for accuracy and function, but you should be very close to that weight if you are using either 4895 or 4064. By best accuracy with all of my US service rifles in 30/06 with the Lyman 311299 bullet is between 1,800 and 1,900 fps. It's the bomb in either Springfields or the M1 Garand and it will hold its accuracy to way, way out there on steel or targets of opportunity.
The bottom line with M1 Garands and cast bullets is that your loads may very well be a compromise between function and accuracy. One has to balance one against the other. It's all good though as once you get one shooting with cast bullets you'll have a load that will generally shoot in any of the US designed Ought Six service rifles.