Using a bottom pour furnace. No way to dip the corner of the mold in the hot lead. Pot no big enough.The Lee instructions tell you to dip a corner of the mold in your hot lead to heat it up. Hold the blocks tightly together while dipping it. Check it every few minutes until the lead doesn't stick to the mold. Then dip the other corner the same way. Don't immerse the joint between the blocks.
This takes less than a minute. If your mold is clean and oil free the balls are nearly always perfect from the first drop.
The instructions also state "or" lay the mold on top to preheat. They never had to state that because I was using that process years ago with an old used Lees mold. After a few minutes I've always been able to cast some nice looking projectiles.
But I have this one figured out now anyway.