What powder charge shoots well depends a lot on the lube used as well. If a very slippery lube like Hoppe's 9 Plus or LehighValley is used, the .40 demands 65gr. of 3F or 75gr. of 2f. When using spit or a windhshield washer/soap mix, a mere 55gr. of 3F suffices. 50 shoots OK, and so does 60, however 55 is the cat's pajamas with this rifle. Interestngly enough, the same charge, ie: 55gr. shoots identically in 2f - which is strange.
My .45 GM barrel demanded more powder - 75gr. of 3f and 85gr. of 2f when using the slippery lubes and 70/80 when using wet lubes.
In order to get to know your rifle, you've got to shoot it a lot.
Both these rifles will put 5 into a 25 yard bull off the bags, that can be covered with a dime - as will the .32, if 35gr. is used. It will shoot a quarter sized group with any other charge down to 25gr., but that charge blow the groups farther out than 25 yards.
The .58's and .69 really don't care how much powder is or is not used for shooting 25 yards. 50 yards and beyond, though, demands a descent charge- no pipsheak charges will group well at 50 or farther.