Heylo Wilbur..
Heat in a glazed ceramic pot and a KK are two different beasts..
Don't worry about your KK firebox.. It's massive and the refractory material's "service/working" temp is 2,200ºf
Charcoal does not get much over 1,800ºf in your grill..
Once it's expanded and contracted a couple of times, never remove it and you will never have issues with it..
Remember don't/never remove your firebox to clean your grill..
They get wedged into place and will get crazing but they are just fine.. leave them.
Baking stone up on your upper grill.. NO heat shield..
First "trial" pizza.. try about 575º dome..
If the top is uncooked when the crust is finished it's not hot enough..
If the top is getting browned/burned and the crust is not ready.. turn it down a bit.
At high temps you only use the top damper to adjust.
Small changes are apparent quickly.
Have fun with them and take photos..