Probably the easiest for your situation would be to go with a Powerbelt. Most of the bad reviews you've heard are probably by people using a lightweight Powerbelt with magnum charges. .45 Powerbelts are actually better than the .50 cal, because of the better sectional density.

I would try out either the 275 grain hollowpoint or the 300 grain Platinum. Start out with 70 grains of Pyrodex and try shooting some groups with that, then increase to 75 and 80 grains to see what groups best for you. I wouldn't go over 80-85 grains of powder. This should be a great load out to 120 yards or so.