In the past 2 1/2 years I've melted a couple hundred lbs of (indoor) range lead in an old steel saucepan over a $20 Cdn Tire hotplate. The clean lead is formed into muffins in an old Al baking pan. Of this I've ladle cast about 50 lbs of various calibres from .30 to .50 with no issues.I've "smelted" over two tons of wheelweight (about three tons of raw wheelweight) using just a stainless steel mixing bowl from Canadian Tire.
I would say the viscosity of lead is just as liquid as water but the added weight make the pressure higher at the bottom of the pot