The unsuspecting lid generously dropped off by @CMHGourmand, you will be rewarded!
The other, and still functional, lid (thanks @ToKateFromKate) sitting beside the newer design. Notice the closer crop/smaller section removed. I also did away with the door, I've never cooked with it closed. The intent was to see what the convection would be like with a closer-cropped opening. I got lots of smoke - bad! Very surprising given the size of the opening.
A sample pizza (ok four) were run through for a test (and light lunch). They were uniformly cooked, but the opening made it a pain to get them in and out and feeding wood was also tougher.
Here's another shot where the thermocouple probe wire is visible (on the left). I placed the probe in the side away from the fire (the "cool" side) hooked up to a datalogger. I maintained ca 800-850°F with an occasional spike. The surface of the stone stayed about 800°F at the center.
The temperature profile on the cool side, the probe was placed just below the cooking stone. It was a short cooking session, this is the hour after a 30 min warm-up.
Given the amount of smoke I saw during the burn, I ripped it open to look more like the previous design opening - only larger. I've opened about a full third of the perimeter. I'll give it a shot tomorrow night. I'm essentially back to where I started (which wasn't a bad place), but I may have slightly more convenient access. Incidentally, I get about an hour and a half of high temps from a $5 bundle of grocery store wood.