Yes this thing is begging for a few mods. First off I made a new charcoal grate because the one that it comes with is garbage.
Then I extended the exhaust down to grate level.
Next I will be working on maybe installing the fire rope around the lid (there's probably 1/4" gap all the way around). For now I've been doing the tango with the darn thing everytime the wind shifts direction!
Next I will take your idea and work with the charcoal pan and make a tuning plate out of it and see how that goes.
As far as that thermometer on the hood, what a joke! My grate therm to the hood therms are off about 75º-100º