OK, I put a 150w 4x5 heater on the oil pan and a 100w 4x5 heater on the trans. Hoping this helps a bit with the ol MPGz!
Trans Heater (on the corner to make the cord the most out of the way possible)
Oil pan heater (perfect fit!) as well as the coolant heater
And thought this was interesting... aerodynamics? Pshhh... who needs those?!