Roll crimping is no big deal. You can buy an antique roll crimper and get good results. Ballistic Products sells roll crimpers for use in a hand drill or drill press. They work the same. I have used both.

I don't have a clue about loading slugs, though.

Here is a batch of 10ga. 2 7/8" shells I loaded for my Lindner Daly, using a Ballistics Products roll crimper. Roll crimping over a ball or slug is the same operation.

Curl