Well I've never found more than one, because I don't look. I choose a bullet for the game I'm hunting, then a ball and an extruded powder of similar burn rates to obtain good, but not maximum performance. I try about 5 different charge weights between starting and less than the maximum load, equally spaced. I develop the most promising load by playing with the seating depth. I've long since standardized cases and primers, just to cut down on options.