The minnie ball ... I would not recommend unless you get the rifle barrel. I have a LEE minnie ball mold in both .50 and .54 I would part with. That is how much I dislike the minnie. Now if you were shooting a military rifle that might be different. The minnie is under sized and so until your rifle is filthy the accuracy for me in a 1-48 twist, never happened. Perhaps a slow twist they would shoot well.

If I were going after a conical shooter it would be a 1-24 twist. And for conicals, I would shoot the maxiball (not the maxi hunter), the Great Plains Conical by Lyman, or a custom slip fit conical might work real well also. If you ever see Lyman Shocker Conicals... run away fast. I have yet to find a rifle that shoots them. Also the Buffalo Bullet is normally a good conical but they are hard to find.