Seems like something you could do with a couple of channel brackets and a latch or two. Run 2 or 3 horizontal channels above and below the heat/smoke feeder inlet into the CC that the weight of the FB would hold firm. Run a vertical channel on the front of the CC that the FB would grab onto for stability. Put 2 or 3 latches on the opposite (back) side of the FB from the vertical channel that would suck the whole FB into the body of the CC to keep them sealed together. Put a high temp gasket between the two. The channels would need to be stout enough to hold the weight and the weld points on the CC would need to be onto the frame, not the skin. I'm thinking this would make the whole thing a bit more modular. Probably overthinking. Too much coffee already ...
I'm attaching a terrible freehand sketch that hopefully clarifies but probably will only be more confusing. Good luck!
View attachment 438269