I built a lesser brand Hawken replica from a kit for the son of a friend who didn't think he could do as good a job as I would.
After building it I test fired it a few times and found it quiet accurate at the short range I was using, maybe 25 yards. Not a real test of its abilities of course.
I only had FFFG pistol grade Black Powder on hand so I used only light loads.
As for recoil any muzzle loader can be used with a charge tailored for the shooter.
A 40 gr charge with round ball is about equal to a Winchester .44-40 in power.
You can go right on up to equal the big Sharps .50 if you use a heavy conical bullet and a heavy charge.
Few of the Hunters of that era used heavy charges, they could not afford to use more powder than necessary , cost of powder being less of a factor than being limited to what you could bring with you into the wilderness.
Lead ball could be recovered from game and melted down again to cast more bullets, but powder and caps were not something the average guy could make for himself.
I've been considering building a matchlock then converting it to wheel lock using a lock of my own design.
A French gunsmith made a few wheel lock pistols well into the cartridge era, locks of his design being more reliable and faster than even caplocks and very neatly sealed against the elements. These are of course extremely rare guns and were even in that era.
The secret is to use Iron pyrites instead of flint.