Honestly, I'd hoped to do both. I've done some reading on the American Long Rifle forums about casting round balls, and for larger caliber, there's a lot of folks who feel bottom-pouring produces voids inside the ball. I'll be pouring either 0.600 or 0.610 balls, so they are definitely a larger caliber.
I figured I'd bottom pour boolits and ladle for round ball casting, but at this point, I'm having fun messing around with it to see what works for me.