I have a twin chamber charcoal grill with the adjustable coal grates.I am going to add a rotesirary(no cut outs provided) as well as extra vents and added steel plateing for heat retention.I am also looking for ideas on makeing it into a propane charcoal combo.Not at the same time mind you. I need a design that is quickly changed from one to the other.I know this is a pretty vauge question, and if any of you have ever tried something so crazy than you are the ones I would like advice from.It would surely be cheaper and safer to buy a gas grill but not as much fun or rewarding.