Just by way of update....
Ran a short casting session last night. Used both cavities, and results were 16 rejects for 54 keepers.
Of the rejects, a few were my own fault for not having enough lead in the dipper and leaving voids.
Some I just didn't like. Can't explain it, but I didn't want to keep them. I am being very picky now and still keeping a good percentage compared to my start. So that's progress.
I'm indeed using a Lee mold, and the sprue plate wants to come loose as I cast. I tighten it again simply because I'm left handed, and i feel better pouring lead with my left hand. I tip the mold inward with my right hand to mate the dipper spout to the countersink on the sprue plate. Then I tip them together back to vertical. This stops lead from dripping everywhere and seems to work pretty well, but with the mold being tipped to it's left, if the plate doesn't have some tension, it'll swing open from gravity. I have to keep at least some tension on that screw so it doesn't do that.
I gave it a tad longer (5 count) before cutting and the sprues look better.
So things are going well.
The balls are shiny and mirror-like when done. When they are a few days old and oxidized, whatever flaws I saw when freshly cast are invisible. They look as good, or better, than the ones I'd bought prior to getting tooled up to cast.
The proof is in the shooting, so we'll see how that goes here shortly. I have a couple hundred now, so I'm gonna start flinging 'em and see what we get.