Looks Great ! I agree that the charcoal basket is your next mod - will really help with the temps.
I keep forgetting to get a picture of my home-made one - which I'll try to do -
As for the temp guage - I hardly use the internal one similar to yours - as I dedicate a digital for that (stick probe through a half potato or similar to keep about 1 inch of grate). But simple soap and water and paper towel will do just fine.