I cast in all temps winter or summer with brass molds aluminum molds , get your mold up to temp , I first wash with soap and hot water then heat cycle it a few times , then start casting with mold up to temp and throw first casts out where I can glance at them when they show fill out and no wrinkles it is down the cushioned ramp to catch basin , spout freezing on my pro melt needed temp up a little more , a little at a time till you find what works , thermometer I have is showing a lot lower then I believe it to be , PID seems right on so it is what I am running by ( yes for years I used no thermometer or PID ) and lead and freeze time seems right torch close by to unfreeze spout when tossing in sprues if needed , level of pot plays a big rule I have noticed in pressure of pour and in staying running when tossing in sprues , I like to keep adding them back and freshening level with ingots as needed , caution on ingots pre warmed is best no need for nasty pops and splatters from ingots , be surprised how one day everything goes in fine and next day there is a splatter from cold or moisture , I have just ran 2 separate MP brass molds last few days they are both brass no lee style lever .