A $3.00 GE Gas Grease Pan sits directly on top of the outer coffee can as a 'focusing' plate.  On top of that is an inverted gas grate - used.  On top of that is a Revereware pot with 850 ML of ambient temp water in it.  About 10C.  At first, I had both the pan and the grate inverted, but this appears to put the pot too close to the top of the coffee can and there was some smoking -- not much.  So I put the Grease Pan right side up, but left the grate inverted.  Solved the problem.