Most expert reloaders recommend a tray of 50 rounds. But if you had maybe a revolver (I like wheels guns a lot but have mostly autos) you could load up 6 light, 6 medium, 6 stout, etc. They recommend, for the novice reloader, to stay strictly with the "book loads". These being recommended loads from a manufacturer. It gets so complex, rather it gets so man y layers of things to check, that I say pretty much best to stick with a middle of the road mixture, and for a few reasons.

1. So you do not push the limits of the gun, cases, etc.
2. These 'medium' loads are usually in the fattest 'sweet spot' for most guns. Will perform well in most anything!
3. Usually best accuracy in most weapons, easiest for follow-up shots, etc.
4. Modest recoil in common medium frame handguns.
   There is a lot of extra prep and attention required if you go into "load research", even in the recommended ranges, if looking for that magic bullet formula for your exact setup. Especially so if you want "Max Power" loads. This is where everyone says "PROCEED WITH CAUTION!"!