Any specific load combo's there is so many combo's it's kind of overwhelming?
Keep it simple to start. Pick up some 209 primers, a jug of T7 ffg granular, a powder measure, some black .50/45 sabots, and a box of 240 grain .451/.452 XTP bullets or 300 grain XTPs and ample patches or chop a t-shirt into 2-1/4" squares. Maybe a few plastic charge vials.
Set the measure to 90 grains. Fill with powder, give a soft tap or two then top off and pour into the charge vial or the barrel. Put a bullet in the sabot and run it down the barrel until firmly set on the powder. Place the primer in the breech plug, cock and shoot. Run a damp patch down the barrel, flip and run again....this knocks down the crud ring that can make a second shot hard if not impossible to load. Now you're ready to shoot again.
Start at the 90 grains. You can increase the charge 10 grains at a time until you find a level that is as accurate as you feel you can get. I think most people find the sweet spot between 90 and 110 grains using the volume measure.
Allow time to clean the gun very shortly after shooting it. Don't wait days when using any black powder or sub, other than the BH209 sub which will allow some relaxed time to clean by a few days. Find a drill bit that fits into the flash channel which is the narrower hole immediately behind the primer pocket in the plug. Use this to hand turn and ream out the carbon in the plug at each cleaning and its easier to do before using any water to clean the plug. Some Dawn dish detergent and warm water will suffice as a cleaning solution.
This will get you on the range and in the field. After you've shot the gun and feel fairly comfortable with it you may want to check out the BH209 powder. Yes, its expensive, however there are some benefits to it that cannot be found with any of the blacks and other subs: cleaning can be delayed until the end of hunting season in most instances, as long as its not more than a couple weeks, as opposed to within a day of firing. The powder does not absorb moisture as blacks and other subs can be prone to. Using it will require the use of full power primers, not those sold as "muzzleloader" primers. Accuracy can generally be tightened up a hair using BH209. BH is solvent clean-up. not the water and the plug's flash channel will still need to be reamed, again before getting any solvent on the plug. In many cases, if not most, you can use the same T7 powder charge using Bh209 that you've gotten you best accuracy from. Velocity I feel is just a hair higher using BH than the same charge of T7. Definitely higher than Pyrodex. If T7 granular or Bh209 mare not locally available, I'd recommend true black over Pyrodex. Personally, I will not recommend using pellet powder of any kind feeling that it takes away any real flexibility in working you load levels up. Again , personally, all of my hunting inlines shoot BH209 in the woods using the same exact volume charge of T7 [fffg] that I shoot at the range. The fffg T7 gives me just a hair more umph.
Congrats on the win! Read a bit more here, get the goodies together and have fun shooting!
I'm just going to add here, when you hgit the range, stay focused on what you're doing! Don't go there to talk while you're in your loading sequence. If you get distracted, pop that breech plug and make darned certain the gun is empty before you dump another charge down the pipe. Als, carry some masking tape with you and when you fill the barrel with a load, leave the rod in there and wrap a layer of tape round it at the muzzle so you can tell if the gun is charged or not. This is a witness mark. Change the tape location each time you change the powder charge. When you reach a charge/bullet /sabot combination that you're happy with, make that mark a bit more durable by using some electricians tape.
