I like my ball alloy (pure) at about 800º or even a bit higher. It helps get rid of the wrinkles you get without any tin.
Lee molds can be a pain at times, but the price overcomes it, at least for me. Probably the biggest thing is the galling you get on the top surface. I use a product called Bullplate lube on the sprue-plate, and it stops lead smear, which will start the galling. All it is I think is a high temp oil. Trust me, a little goes a long ways. As you might know, any oil in the cavities will cause bad balls, so you need to be careful. I've heard that you can use a spray graphite on the sprue-plate, but haven't tried it myself.
When I get a new Lee mold, I'll go over it and get rid of all the sharp edges that aren't part of the molding surface. They don't de-burr anything they don't have to.
You also need to clean the cavities really good. Brake cleaner, acetone, whatever. The cavities need to be very clean, and the cutting oils they use are left on. They don't clean any more than they have to either.
Balls cast a bit different than bullets, but if you know how to cast one, the other won't be a problem.