Very nice rifle! Well done.
As to loads, you can use whatever you want - however, in my .45, 42" bl. with 60" twist, my plinking loads for a water-based lube used for target shooting, was a .445" ball and .022" denim patch.
With a nice smooth crown, this was easily started and shoved home on the powder. Almost the same accuracy, not quite - maybe 1/2" larger but still at an inch at 50yards, was the same patch and a .440" ball. That one was VERY easy to load (they both were) after multiple rounds - say, up to 50 or 60 shots on the trail, with no wiping and no loading problems. The only buildup of fouling is in the powder chamber area, which was not much.
I would never consider using a ball smaller than .440" as the pressures are very much higher in the smaller bores than the larger ones.
With a water based lube, I found 65gr. of 3F worked just fine with my preferred .445" ball. If using a slippery lube like Hoppe's #9 Plus black powder lube, or LHV, I had to use 75.0gr. of 3F to get the same accuracy. I also found that 85.0gr. 2f GOEX gave me the same accuracy with the .445" ball and .022" patch, that 75.0gr. of 3f gave. Too, the velocities were almost identical.
A water based lube, ie: Winter Windshield Washer Fluid + a couple ounce of Neetsfoot oil per liter of fluid, made a terrific cold weather lube as it did not freeze. In hot weather, the oil slowed the evapouration rate as well, so a bunch of us use this all year.
The points of impact were very close to being the same, with the slippery lube and high velocity almost the same poi.
