Nice to see someone putting this into practice. I posted about this about one yr ago ( http://www.hookahpro.com/forum/showthread.php?t=7521
) was pretty much shot down. AAny way . .I think you should have a double heater - as in very small element that reaches the temperature of a standing lit coal ( not fanned by inhaling) and a separate air heater like the ones in hairdryers that only light up when you take a drag - You could to that by runnin a switch to your hose handle and pressing it a second behore dragging on it - that way you shisha will only heat up occassioanlly and will not stat burning. Also try to find a heating element that does not oxidize, will eliminate the metallic taste.