Zoli 58 cals will shoot round ball very accurately as well as Minie bullets.
The only way you will find out is to have fun shooting it.
Just remember to use pure lead.
With round ball start with forty grains of FFg
With the minie start with fifty grains of FFg.
This should have a musket cap nipple - very reliable
you can replace that with a No 11 nipple as well (available from Dixie gun works)
If you use the minie for hunting work up a load. There will be a point where accuracy falls off due to the skirt of the bullet blowing out because of excess pressure. That point depends on your bullet, lead alloy, powder charge, and gun.
You can use pyrodex but make sure you clean it immediately. Pyrodex has a potasium clorate base and is MORE hygroscopic and corrosive than black powder.
I do not use pyrodex in any black powder firearms any more.