Don H. - I did almost exactly what you're describing, I think. I also got a Centaur fireport and placed in a cut out in 1/4" plate. The flanges left and right are above the plane of the plate, but the front and rear are at the same level as the plate surface. There was a gap front and rear, but I placed angle iron in them and that worked. When working, coal is piled around the sides and rear, so the raised edges of the pot aren't apparent. The side draft chimney is metal 10" stovepipe sitting on the plate inside chimney block, bottom one and some cut out as is the pipe in an arc. The whole affair is sitting on top of four columns made of concrete block piled up - no mortar anywhere. The plate is 4' x 4' with 1" square tube welded all around the bottom as a frame, very heavy, very stable. The whole thing can be taken apart easily and reassembled. It works great, has a large work area, and I can forge weld with it.