Using a hot plate was one of em'. Have been casting smaller sized batches and weighing each bullet. The hot plate is PID controlled via the hookup shown in the photo. Mould is a DC Lyman 452374 which I've also modified to help the front cavity average to be as good as the rear one. So far into around 10 sessions and weighing the first bullets out of the mould they're staying within 0.5 grains or better than the batch average using the hot plate instead of the old warming shelf's I had added to my pots. So far with the mod on the mold I'm staying within ± 1 grain of average weight bottom pouring 90% of the time which is better than I shoot anymore!
Also monitoring mould temperature with my VOM has been enlightening. You don't have to change your cadence very much to change the temperature 10° or more! This mould seems to work best at about 340° F and setting the hot plate at 390° gets the mould darn close while the pot heats up.
I think I cast fairly good bullets before thermocouples and PID's but they're a little better now and it's nice to just turn on the switches and in 20 minutes produce more consistent bullets than before. Eliminates a lot of guessing for me at least. 390° seems to work to get the mould up to temp.
Another tip picked up on here is nothing ever goes into my pot but clean metal and beeswax. That last item really made life simpler keeping the pot clean.