Most use a .350" ball in a .36 cal. gun. It should not be difficult to load.
It all depends on the shape of the crown at the muzzle of your gun, compared to the diameter of your ball, and the thickness of the patch.
You might also consider coning the muzzle to allow you to load the PRB without the need of a short starter. I like to be able to thumb start my PRB, and leave the short starter in my range box to use with other guns at the range. :surrender:
Consider that the .36 is basically a 50 yd.* caliber, and most all barrels made today will give you the accuracy needed to hit small game, if you do your part, out to 50 yds, I see no need to be hauling a heavy target rifle in .36 cal. to the woods to use to hunt game. Nor, do oversized balls, and thick patches seem to be required to kill squirrels, and rabbits, or varmints. :hmm:
* Yes, I know that may fine shots have been made out to 100 yds, and beyond, using this caliber RB, but the little 65 grain ball is losing energy at an incredible rate, even it it still has a relatively flat trajectory. Unless You are shooting coyote, I think taking 100 yd shots at anything less just increases the chances of wounding game that will suffer a slow death, if you can't find it. 50 yds.(150 feet) is a long distance for an open sight shot, with any caliber rifle, shot off-hand, as so many hunting shots must be. If I sound conservative in rating a .36 rifle, it is not because I do not know its capabilities in the hands of a skilled shooter. The Great shooter know how far they can hit a small animal with a .36 RB, and all that I have met and known advise staying within 50 yds.