If you do not need a screaming hot kettle for your pizza, I find the following a good method of doing pizza and calzones. My setup will run around 425-450 degrees and I think it does protect the kettle pretty well.
The setup I use for my hot lump coals.
I use a ceramic plate setter with my hearth stone on top and this makes a wonderful base for my pizza.
A nice size pizza going on my hearth setup in my Weber kettle.
First pizza done on the kettle and I usually follow up with a second pizza.
Second pizza done on cooker.
I followed my two pies with three calzones.
Calzones on the kettle.
Results of my Weber kettle bake.
Anyway, this works for me and I am happy with the results.