Most people recommend to start your rifle out around 70 grains of Goex 3f. Then work upward. I personally start them at 80 grains and they usually come in around 85 grains in a .50 caliber sidelock. It's just less goofing around. Actually they will shoot real well with the Goex 3f and I think you will be surprised at the lack of fowling, then what you might be expecting.

I shoot Goex all the time and the stink, smoke, and fowling don't bother me one bit. Sure I like clean burning powders, but I also like to see the whole back yard full of thick gray smoke after I shoot. It always puts a smile on my face...