Jerry, I don't want to sound negative, but I also have this particular mould you showed from Lee, and in my own experience it is pretty bad for having a thin, easily blown, skirt.
IMO, the cavity is too deep, and the skirt is too thin for hunting purposes....it is nice for paper because it is OS. On the other hand, for plain paper punching with a Minie, it is hard to beat the Lee "Trash Can", or Modern Minie.
For hunting, any of the Parker Hale type are better, and Lymans 575213PH is one of the best, albeit in .58 cal.
I would suggest a REAL or a Maxi over any hollow base mould for heavy loads in a roundball twist....with a solid base you can actually "increase" the powder charge to improve accuracy, whereas with a hollow base, when you reach a point where you are blowing the skirt, you must decrease the powder charge in order to find accuracy.
Minies are not designed for accuracy, but for field expediency. This does not mean that a proper fitting, proper charged minie can not be accurate, because they can.
I think however, in a hunting application, velocity and heavy charges are an important consideration.
In Marks case, where he is looking for an accurate, yet heavy hunting load, I would recommend a solid base conical, or a heavy skirted minie, of no more than .004 oversize.
BTW: You find the usage of O.S. on two different makers of moulds...on Lee Moulds, it means "Over Size", on Lyman it means "Old Style"....not that one is necessarily better than the other, because as a rule you do want your projectile a bit oversize from the bore, and you have to physically measure your bore to know it's actual dimensions.
Uncle Russ...