When I load 45-70 cases with 50+ gr of Varget or H335, I don't use a wad. The case is almost full, no no need to keep the powder on top of the flash hole, even when the loaded cartridge is horizontal.
Different story altogether when I use 11 gr of Unique for my 'powderpuff' loads. That little bit (relatively) of powder when laid out horizontally may not be anywhere near the flash hole (and the primer flame) so I place a vegetable fiber wad (bought in bulk from one of the cowboy action sites) atop the powder before seating the bullet. I use a proper-sized stainless bolt (from Home Depot) to push the wad into place. A sharpie line on the bolt lets me confirm the wad is in the proper spot, so I know there is the right amount of powder in the case.
No experience with BP in any of my big bore guns. My apartment landlord would likely shit a golden brick if he found me storing BP in my place!
M, I was looking at the Wen version. Most reviews seem to be good.