Commercial casters & salty gonzos use turkey fryers + large pots to process large amounts of scrap into ingots or pour large castings. If you manage to find a large supply of hundreds of #s or more of scrap, and you will if you keep looking, that setup will optimize your time efficiency. Scrap is out there waiting, recently I was offered 16 full buckets of wheel weights.
An electric coil hot plate is really slow and DANGEROUS as it is not designed for the weight and temp of molten lead - I use the smallest size cast iron propane burner designed for cooking I believe and it works fine for my 15-20# cast iron pots for jig head casting and 3 qt. HEAVY GAUGE steel pot for processing scrap into ingots or larger sinkers.
Sorry Doc, I know you're horrified by my suggesting gas as a fuel source, but it is the most efficient way to heat lead melting pots.