You might want to buy a few different weights and design types of 58 minies and try them before buying a mould.
Some shoot better than others just like any other firearm.
Dixie or Track of the Wolf usually has cast minie bullets you can buy. I'm sure there are others.

How and what you lube them with can make a big difference in accuracy too.

I didn't find any of them more accurate than a .570 patched RB in my .58 Zouave. But the minies were surely more convenient on the range especially using some old skirmish loading tubes..