.575 ball is 286gr
.610 ball is 342gr
.715 ball is 550gr.

I can't find any hard data on velocities for large caliber with stout loads but I'm sure they could probably be gotten up at least into the high 1500s. Assuming my shoulder can take it. lol

A .58 double would be easier to handle and with a good thick barrel and/or chamber liner type breech plug could handle some serious powder charges. A .62 would be a little better but considerably heavier. With real strong loads and harder alloy balls you could cook up some good penetration. Especially at shorter ranges. (I only started shooting MLs after messing up my shoulder too badly to shoot a longbow anymore, so I still want to try to limit myself to near archery ranges.)

I have looked at the Ped .72 and have a Ped .50 double. They are nice rifles but aren't really regulated. My understanding is that they are aligned with a laser and that's it and you have about a 1 in 4 chance of a good regulation. My Kodiak .50 has about a foot of separation at 50yds, which is wholly unacceptable. And that's after a considerable amount of fiddling with loads. I would much rather get 2 match quality barrels and go through the drawn out process of joining and regulating them. There is an immense satisfaction to taking game with gear you made yourself.

I had also thought about getting a set of the Pedersoli .72 barrels and detaching and regulating them myself. But a set of barrels from them actually costs more than getting 2, .62 cal, match quality barrels made. So if it's actually less money for higher quality, why compromise?