Sounds like you are off to a good start. Play with the roundballs, a lot cheaper to shoot than maxis. They will also do the job just fine on deer. My most memorable deer with the ML was a nice buck at 80 yards, pass through shot. He had his head in a bush when I shot and I had an either sex tag, it was a nice surprise to see antlers when he wheeled around after the shot.
For those .530's you need a patch that will make them tight in the bore, I think a .015 patch would work. I would stay away from Blackpowder and go with a substitute, there are lots of good ones out there.
In case you have not yet found this:
http://www.lymanproducts.com/lyman/muzzle-loaders/pdfs/lyc-ml-general.pdfMaximum Loads
Lyman Black Powder Guns
The following loads are maximum combinations of propellant and projectile
for Lyman Black Powder guns except for the Mustang Breakaway Rifle
which can be found on page 44. Do Not Exceed!
Plains Pistol
.50 - .495" RB 40 grs. 3Fg
.54 - .535" RB 50 grs. 3 Fg
Rifles
.50 .495" RB 110 grs. 2Fg or 90 grs. 3Fg
240 gr. Sabot 100 grs. 2Fg or 90 grs. 3Fg
335 gr. Sabot 100 grs. 2Fg or 80 grs. 3Fg
420 gr. Maxi 100 grs. 2Fg or 80 grs. 3Fg
.54 .535" RB 120 grs. 2Fg or 100 grs. 3Fg
335 gr. Sabot 110 grs. 2Fg or 90 grs. 3Fg
450 gr. Maxi 110 grs. 2Fg or 90 grs. 3Fg
Round Ball Selection Guide
.50 cal. .490"/.495" .54 cal. .530"/.535"
Note: Equivalent loads of Pyrodex RS, Select, or P are acceptable.
Pyrodex pellets are not recommended with Lyman side hammer guns
due to difficult ignition.