If legal, the bare 209 primer conversion is well worth it. I have the plastic jacket 209 primer setup for my Knight TK2000, but I don't use it anymore. The plastic jackets are fine, and they are cheap and can be reused plenty, but it's still another thing you need which has no real benefits. If it is more waterproof, I sure can't tell. I actually prefer percussion caps most of the time, they tend to shoot better with black powder, and they are easier to handle in a capper.
I've shot quite a bit of BH209 powder back when it was $30 for 10 ounces, and it wasn't even that long ago. Today at $80 for 8 ounces, man. It's worth a try, but don't marry yourself to it. Buy one bottle and try it, it's always good to experiment. You can get plenty of info on the two other biggest name substitutes 777 and Pyrodex. Don't discount real blackpowder Like Swiss or hopefully Goex comes back with their Olde Eynsford either. If you can find it, the stuff can be really accurate, and the reliability is unmatched.
Speaking for BH209 specifically, there's only two primers that have been recommended for it, and thats the Federal 209A and the CCI 209M (NOT the regular CCI 209, which is far too weak). I have heard of people getting good results with Winchester 209's, but I'm not sure I'd bother to try them. You are going to have a hard time finding any of those primers. Muzzleloader specific 209's will not work. Cheddite and Rio 209's can be had, but they are probably too weak for this. Some of this has to do with what you are shooting. If you are shooting a heavy, say 400+ grain bullet that also has a good seal, then you can probably get away with a weaker primer. My advice is to just find some Federal 209A or CCI 209M, they are the best ones you can use. Watch Ballistic Products, they sometimes have pulldown Federal 209A's, but they go quick.
BH209 I've found needs a good seal. It's essentially a smokeless powder, so it needs to build pressure before it really ignites. Mostly this is a nonissue, but where you can run into issues is if you are shooting a full bore conical like a Maxiball, or a No Excuses bore size bullet. Those bullets are not sealing all the way to the groove diameter, so they need to bump up during firing. The fix for that is easy, and it's usually a good practice with any powder, is to use wadding. Generally 1/8" or 1/4" thick felt wads are plenty to to the job. Max loads of BH209 depend on the rifle, but generally 120 gr by VOLUME is considered maximum with most bullets, and most 50 caliber rifles. A lot of people end up weighing their charges of BH209 for maximum accuracy, so be aware that BH209, as well as every other substitute powder is listed by VOLUME only. It appears the BH209 can vary in actual weight by quite a bit lot to lot, so I'm not sure what the maximum charge by weight would be. Just use a 120 gr volume measure, and weigh that. Generally I found my best accuracy in the 75 to 100 gr volume range. 120gr volume of BH209 is pretty dang hot. You will find that velocities with BH209 are usually higher than expected.
When it comes to bore care, BH209 doesn't seem to clean well with water like blackpowder or other substitutes. Instead a bore cleaner solvent is needed, I found Hoppes #9 did fine for me. The breech plug can clog up with gunk, but I'm not sure if it's any worse than 777. All you need is a drill bit the same size as the flash channel, the large diameter, not the tiny little hole. It's like 1/8" or similar. Just run that bit in there with your fingers and it cleans that crust out in no time. Inside the bore I think most people just shoot and are fine. I like to swab between shots. If you run a patch, I would either leave it dry, or use alcohol. I did not have much luck with spit with BH209. A single patch is usually fine, BH209 fouling is not bad at all. Once you are done shooting, I found best results as said with a bore solvent like Hoppes #9 and a brass bore brush. I cleaned just like a centerfire rifle. Which reminds me, you will probably want a range rod, I'll get to that next. When it comes to hunting, one benefit to BH209 is you could hunt with a fouled bore if you plan it right. It really depends how humid your environment is, but I feel you should be fine with a fouled bore and BH209 for a week. I wouldn't push it to a month, that's asking for rust. It's "non-corrosive" powder, but it's really less corrosive. The fouling itself, both from the powder and primer, is still there, and it can absorb moisture from the air.
Now as for some general muzzleloader shooting tips, the #1 thing is you will want a range rod. The ramrod on your rifle is fine for loading a shot in the field, but it's not the nicest to use. The very best one I've found is the steel ones from Track of the Wolf. I'll put a link to the 29" one below, which should work fine for most inline rifles. There isn't much for 30"+ barrels until you are looking at traditional muzzleloaders. They make those rods up to 44" if you want them. These rods are rock solid, the bore guide is very nice for preserving the muzzle. They make loading very tight fitting bullets a breeze. I use mine for cleaning too, but if you want a second rod for cleaning, TOTW also sells Delrin rods which work perfect for that. Delrin is some kind of plastic. I absolutely HATE them for ramrods, but they are perfect cleaning rods. You can get all the jags and stuff you want from TOTW too. If you are going to shoot mostly pointed bullets, you will want to pick up a loading tip made for them. I'm not a fan of those universal tips, they don't do anything great. I like the TOTW jags for loading round ball and other blunt bullets. I think Spinjag is a big name people use for pointed bullets. You can buy cleaning patches, but I find old T shirts work even better. Lastly, you will want a decent short starter. Some bullets load fine with no starter at all. Some, especially plastic sabot bullets are extremely hard to start. Don't get a plastic one, they are knuckle busters. You will probably want one with removable tips so you can screw in your own loading tips. It's too bad Thompson Center is out of buisness, they used to make a really nice aluminum one. A quick search shows Knight makes one that should work perfect for you.
Our Strongest Loading & Cleaning Rod, 5/16" stainless, over 29" long for Lyman Trade Rifle or T/C Hawken, Creedmoor, rigid handle, 10-32 thread
www.trackofthewolf.com
