I recently got an old Oklahoma Joe smoker. It's not the big Longhorn model. Its got about a 30 " long cook chamber and has a16" round body. I would like to add tuner plates. My question is how much below the grate should the plates be? There is an angled baffle that covers part of the firebox opening. If I build off this baffle I will be about 2 1/2" below the grate. I can raise the grate another inch if I have to. Is that enough clearance? I don't want to put the plates any lower in the chamber because I don't want to resrict the heat flow under it too much. There would be about 3 3/4" at the lowest part of the chamber clearance this way. Any advice would be appreciated.