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I like the 50 cal. (.512) Hornady 240 gr. Conical using a 1/66 twist, but had to think what powder loads I needed.
I would head to the range and try out a few loads to see what your gun likes.
On the pellets and in line, you did not miss a thing. But thats just me.

Welcome Back..!!
First thing I'd do is verify the twist rate of your bbl. If it's 1:66 or slower...go with roundballs. If it's the more common T/C 1:48 any of the big "conicals" will work great for what you want to do. The T/C "maxi-ball" for example is a good choice. The Hornady 385gn "Great Plains" has worked well for a buddy of mine.