I have not tried wonder wads in a shotgun, or fowler. I have used them in both a revolver, and a rifle.
I believe that Roundball recommends that if you use the felt wads, that you go to the next size larger to insure a good seal. I don't know if 9 or 8 gauge wads are available, in the wool felt wads. ( Circle fly makes such in the OS cards. ) You would have to use those oversized felt wads to insure consistent sealing and chamber pressure with the felt wads. Again, measuring the bore and chokes is very important to being able to choose the right diameter components to load the gun for efficient shooting.
Of course, you can buy your own punch, and cut the felt wads to whatever diameter you desire, out of weather stripping, or old felt hats bought at Goodwill stores, etc. But, first, you have to decide on the correct diameter of the wad for your gun. Since Circle Fly sells wads for every gauge imaginable, I think you should start there. Once a load is found, then you can think about felt wads, punches, etc. NO?
Don't think that you are going to make that 10 gauge into a slamming 60 yard gun for ducks and geese. Or even for turkey. If those chokes can give you good pattern out to 40 yards, you are very blessed. Black Powder is just not going to give you the same RANGE of patterns that smokeless powder does.
The blessing is that you also don't suffer the recoil that smokeless powder delivers, even in these large bores. Learn the limits of your gun, and pass on shots outside its working range. The successes you have will be truly "trophies" to talk about and remember the rest of your life. :hatsoff:
Any lube you desire to use will work. Its main purpose it to protect the bores from rusting in the damp weather outdoors. The next reason for lubing is to allow the shot to slide over the greased bore, rather than rubbing off lead, and putting flats on the side of pellets. Flats will make the pellet slow quickly and drop out of the pattern. What is the point of loading shot into a barrel to shoot, if 1/2 of the shot doesn't reach a target beyond 29 yds?
Go ahead and try Ballistol. I am using Young Country 101 lube because I still have some left from the first large bottle I bought years ago. Its part oil and part beeswax, and I like the wax in the barrel to hold the oil in place. The wax seems to melt under the friction of the load going over it, and that helps to keep the fouling soft for easy cleaning.