I use and like Walton’s Hickory smoke powder. However, I see it as a spice to be mixed into sausage, to get a smoke flavor when I don’t feel like smoking.
If you are going to smoke your bacon… then why add smoke powder? You already get plenty of smoke flavor from actual smoke, and if you want more just smoke a bit longer! In general, smoke powder and liquid smoke are for use when you want that flavor, but don’t want to actually smoke it.
The smoke powder is just maltodextrin that has been massively smoked. It isn’t very water soluble, seems to clump up when I mix into water with spices. You could certainly add to your bacon in a dry rub, but I don’t think much would penetrate, and if you rinse, it will be washed off.
I think a better method, if you just want to try adding smoke flavor to something before you smoke it for 7 or 8 hrs, might be just wipe the slab down with liquid smoke of your choice before adding dry rub. I think that would get better penetration.
Good luck, let us know how it works out if you do it! Especially cool if you did one with, one without, and compared.