After all the body panels were installed and the doors hung, I measured the gaps around the doors. They varied from approximately 1/8" to 3/8", and the door skins weren't flush to the body skins in all areas either. I know most of the MG's I've looked at have similar conditions, but I've always liked the clean appearance of consistent gaps and smooth contours, so I spent a couple days with welder, grinder, filler and sander; and got the doors flush to the body in all areas, and the gaps consistent at 5/32" (.156). I still need to make a tool to put a consistent 1/16" radius on the edges, but it already looks much better than it did a week ago.
Update: I finished off all the door edges with a radius off about .075"- looking good so far.
Since things are already getting out of hand welding up all the body seams, I thought I would seal up the gap between the front fender and the inner fender (at the front edge of the doors). I will be pumping hot engine compartment air through the fenders to evacuate the engine compartment, so I'd like the area sealed to prevent tainted air from leaking inhto the passenger compartment, as well as reducing any whistling due to air leaks. I welded metal in the gaps, then ground it smooth and primed it. This should paint very nice when I finally get around to it.
To keep the heat down in the engine compartment, I am installing vents in the fenders. I like the portholes (ventiports) from the 61 Buicks, and after much searching, I have enough to put 3 per side. These will be force fed by a 4" 250 CFM blower in each front fender. These blowers are used for brake cooling, cockpit ventilation, and bilge ventilation, so they should be OK for moving the hot air out of the engine compartment. I will need to rig a thermostat and a couple relays to provide power to the fans, and fab some brackets to hold them in place, but the concept seems sound.
Even though I didn't have to replace the whole right rocker panel, the front area had some damage that had to be patched prior to replacing the fender. The right fender needed repair as well, so I've installed the patch panel, and welded all the seams.