I use an 1100 watt single coil that I got at Ace Hardware ("Broil-King" I think).
Every saw blade I tried has warped so that heat transfer to the mold was slowed. There's also the fact that I can be clumsy and once scratched the block of one mold on the teeth (just cosmetic, but still). I'm now experimenting with thick strips of aluminum and a mold "garage" made from an old bread pan.