Muzzleloader barrels aren't consistent diameters. You'll just have to try them in yours. I shoot .452 bullets in .50 x.45 sabots without issue in mine. I also use Harvester crush rib sabots, which are a little more forgiving.
They have at least once. I will try to remember to check my packages for diameter statement. They are 50/.44 sabots and are black in color. Will report back with either .429 or .430 or whatever it says.
T/C and/or maybe Hornady had some 50x44 sabots made in black. Most 50x44 sabots are green. All of those are MMP sabots as far as i know. If you need one that loads easier try the Harvester EZ load sabot. If you need one thats even easier to load you will need the Green Crushrib sabot.