I did not think you were actually using ice. That may work for a bait with large appendages but if you have a mold with thin ones they will be hard to fill. Your best bet is to keep them at a warm working temp. Setting them in front of a fan will keep them from over heating. Clamping them with other molds not being used will work to but when they get hot it will still take awhile to cool down. As for putting your Pyrex cups on a griddle, I have been doing that for awhile. Does not work unless you stir it once in awhile to keep the skin off the top. My main cups I never reheat just remelt the sprues and add them back in the main cups. Give the ones on the griddle a little temp boost. I use a high sided one in case of a spill and it won't get knocked off. I have a bunch of videos on you tube showing how I do it. Look me up and watch a few. My channel is Franksrooty2 , a couple of them are in the tutorials section on this site too.