Cal - nice rifle.

I've found the best place for wads is the workbench or kitchen table.
Cut the grease wads from pure wool felt, get the hard stuff, found via McMaster-Carr or elsewhere.
The gas cards are cut from milk carton material, waxed card stock.

I've owned and run a few bore rifles, and I'm not at all a fan of the thin brass shells when used in chambers not specifically cut for them.
It really takes a lot of work to get the load running properly compared to paper or plastic.
I only run the metallic case where absolutely necessary.
If your chambers are in between the thin brass and standard paper or plastic, just have Rocky Mountain Cartridge make some special for your rifle and be done wih it.

See images below.
The first photo shows my felt wads with ball between the tips of the black tongs. Ball, ring shaped or 'donut' greased felt wad, then greased felt disc wad.
These go over the milk carton cup wad (seen formed in steel ring) which sets over the powder.
This setup works very well from mild to super hot black powder loads.
Run roundball over bore diameter - a few thou over is good.
I alloy pure lead 1:10 with tin.