The mold temp is sometimes more important than the lead temp, especially with these brass molds. You have to really heat this thing up. My first ever pour with this mold, I set my hotplate on medium setting for 20 minutes and it was good. Second time around, it seemed I just couldn't get rid of the wrinkles completely. Decided to re-melt the ones I casted and started over. Set the mold on the hotplate on medium for 20 minutes, then cranked it up to high for another 10 minutes and they came out beautiful.
BTW the lead temp I keep around 725 deg.