I have no experience with moly but the word on the street is that you can't switch from moly to non-moly without a complete cleaning of your barrel. So if you're using moly bullets you kinda got to stick with moly bullets. You'll find the 52, 53, and 55gr bullets will shade the 50's when you get downrange even tho they start out a bit faster.
I like ball powder because it is so easy to work with. And my choices in desending order are H-380, H414, and Varget.