Tried a different tact today, stuck with just one mould, for lots of casts. (first attempt with hollow point pins ). Heated pot to about 760 (Pro-Melt bounced between 740-770).
Slowed down a bit, ended up doing about a 5-count between the sprue frosting and cutting it off; if I went any faster it seemed to stretch the HP. Yesterday it was about a 2-count. Also closed the mould a little slower, yesterday it was drop-click-pour.
Good news is I only had about 12 with wrinkles at the start (heated the mould longer on the hotplate). Bad news is I now realize just how lousy yesterdays boolits are - they're headed back to the pot.
One thing I noticed though, while the base and middle bands were well filled out, the top band would occasionally be filled out on one side, but rounded on the other.
I'm thinking a bit more heat, say 775-800 might cure this?
Jim