Greybeard gave you a very solid answer. Perhaps the most sound advise is, don't beat your mold up trying to be fast, nor sacrifice quality for speed. I can make 800 per hour with a 4 cavity, till the pot runs out of lead, half that with a two cavity. LBT molds in both instances of coarse. If I were using an iron or steel mold production would go down to about half that or quite a bit less. They just don't dissapate heat fast enough for highest production.
I know quite a few casters who couldn't care less about production, as a couple hundred bullets at a time is sufficient for them. Besides, for most reloaders, casting is something to do in our spare time, and a lot better than watching the boob tube.