That'll all depend on what bullets and weights along with the powder you want to shoot. Generally your muzzleloader specific primers are fine with the true black powders and subs like Pyrodex and some of the pellet stuff. Personally I'd stay a long way away from pellets and seek out granulated powder.... much more cost effective and much more versatile. T7 granular and BH209 I suggest full strength shot shell reloading 209's. Right now Cheddite 209s are pretty common and will work well with either of the last two powders.
Charge weights or volumes will depend on bullet weight and whether you want to soot bullet to bore or use a sabot. Sabots are the most forgiving way to approach your new gun.
Generally speaking as a started load for the 50, if you choose to shoot either T7 or the BH209, I begin with a 90 grain volume charge of either with a black sabot and a 250 grain to 300 grain, .451 diameter bullet, such as Hornady's XTP. Buy the bullets and sabot in bulk, by the 50's or 100's, cheaper per shot than packaged bullet/sabot deals. Green sabots will work with bullets in the .429 or .430 diameter and a 240 grain or 300 grain bullet can be started at the same 90 grain by volume charge to get you running.
In your gun I'd expect to see the sweet spot somewhere between the 90 volume grains and 110 volume grains. Maybe as high as 120 volume grains but likely lower.
In your shooting, be sure to try a couple different primers after you've got it dialed fairly well. A primer change can often tighten or loosen a group and you'll want to be aware of that should you need to make a primer change due to a shortage or whatever.
Keep things simple to start and begin at a confirmed 25 yards. Once things are shooting tight, move the target to 100 and begin to work on the best group.
Good luck on your quest and welcome to Modern Muzzleloader!