If you do a search on "baffle plate" it can be a problem, but most guys build smokers that way. That would be a good use for some of that 1/8" material you have. The upper air vent in the firebox helps almost as much since it moves cooler air across faster. But, yes, it will be hotter there, for sure, how much depends on how well the smoker flows. Most guys declare victory if it is 5 degrees of difference across the grate.
Yes, you would cut there if it is the right height, it's just harder to mark the same height around the dome, that's why I suggested using a block and a marker.
I only have a few small straps of 1/8" stuff. Bought a piece of 12" (?) pipe. Was going to cut it into sections, cut the 1/8" into "spokes and attach them to a piece of 1" dom for use as a wheel.
The tape was just to make the picture easier to explain. Will be using the block and sharpie to actually mark the cut area. How far back into the cylindrical section of the tank can I safely push the fire box?
The RF plate thickness. Last I was in the scrap yard they had some chunks of 3/8", which if I remember correctly is the limit for my plasma cutter. Would hate to have bought them and not have been able to cut them...