When I cast its usually for more then 1 caliber at a time. So, while my 20lb bottom pour is warming up I de grease my 4 cav lyman steel mold, let air dry and use Frankford easy drop on it. Set it closed on a elec hot plate to warm up. Then get the 6 cav out and check it out and smoke or spray it. I also use a Q-tip and oil guide pins and round line up pins. Set that on hot plate. Add more lead to pot to top off. While thats melting I set up whats needed, gloves, safety glasses, drop pan with several layers of denim as I remove each layer when I get a few hundred on it. By the time I grab the 6 cav, I have no return to pot as well heated evenly and cast till pot low, redo, and then get to 4 cav steel and no heating needed and all 4 good.
Set pot temp at 7.5 by dial and turn to 7 by time I pour, when add more put back to 7.5 and pour at 7. I guess I need a temp gauge, maybe one day.