I checked my 2nd, 3rd and 5th Lyman Shotshell books - only bird shot and buck shot loads, along with some heavy (tungsten, I assume) shot loads in the newest, #5 book.

Now, any of these loads would likely work with round ball or slugs of the same weight - trouble with that, is they are slow as they use faster burning powders.

If real SAFE powder is desired, then black powder, card and fiber wads and round balls will provide REAL power - just as they did back in the 1980's through 90's.

I would expect 8 to 10 drams being normal for round ball loads. Likely should check Green's Book.

Just did, page 689. "The Gun and it's Development"
10 bore - weight of ball 670gr. listed as .775" (should be 700gr. in pure lead) charge 10 drams (273gr.) weight of gun 11 pounds.
Vel listed as 1,600fps, muzzle energy 3,929fpe. +2.5" at 50yards, zero 100.