Howdy. I tried to post this last night, but it didn't take. In regards to your question about Pyrodex being the Wolf ammo of blackpowder, I was going to say this:
Pyrodex burns at a higher temperature than real BP. This is important b/c a sidelock (flint or percussion) doesn't generally put out enough heat at the primer to ignite Pyrodex reliably. It works well in in-lines because they tend to use shotgun primers, and they are much hotter burning than regular caps and flint/BP priming. The other reason is that with an in-line having the primer directly in line (hence the name) with the main charge, you get almost instant lock time. But Pyrodex just doesn't work reliably for most people in a flintlock or caplock gun.
Having said that, most folks who haven't shot sidelocks much often think they are really slow and unreliable. Side locks can be slow, but that's almost always because they are either poorly design or more often, not cleaned properly. If you get a properly built side-lock and keep it properly cleaned, they are quite fast. If some one really wants instantaneous lock time, get a cartridge gun. Yes, side-locks are marginally slower than cartridges due to their design, but because they are, learning to shoot one well will make you a better marksmen all around. They make you slow down, think more, squeeze the trigger more slowly, follow-through longer; basically they require a higher degree of all the basic skills, and will make you better as a result.
The main reason Pyrodex is popular is because it's cleaner burning than BP. This is somewhat annoying, because it does take longer to clean, but I believe that the benefits far outweigh this. BP's other drawback is that the BATFE has it listed as a class A explosive. Private dealers usually can't sell enough to make it worth the effort to navigate the red tape. But even with that being the case, BP still doesn't usually cost any more than Pyrodex, especially if you get BP in bulk. But even with it being listed as an explosive, that doesn't make it more dangerous. Gasoline is very explosive, but we don't often worry too much about it. Just keep it stored in a cool, dry place. I don't know about the fridge, b/c it will absorb moisture, but it should be fine if kept sealed in its container.
Bottom line, real BP is more reliable (to me), especially in a sidelock. It's cheaper over time. Side locks with real BP make you a better shooter. But whatever you choose to do, have fun with it and keep working at it 'til you find what works best for you.