the grooves determine the amount of lube, which is a big deal with black powder. keeping the fouling soft is critical to accuracy. if you don't have a
mould already, one with lube grooves cut for black powder is a good idea.
I like S.P.G. but there are other fine lubes and formulas out there. I prefer
cardboard , felt, or vegetable fiber wads, not plastic.
Powder should be compressed, how much is often a matter of debate. I don't bust a gut trying to compress it, but i do like it packed.
Talk to some of the b.p.c.r. guys if you get a chance. There is a learning curve ( i'm still in it) but fun using black.