Craig, I don't ever look at air temperature. Air temp is insignificant in fast baked pizza- at least in non LBE settings. A probe that measures the temp of the air flowing over the top of the pizza in an LBE might be useful, but air temps in almost all other settings are pretty much meaningless. Convection heat is influenced by air temp and convection is a player in WFO/other ovens, but, in these environments, the rate of the air flow is far more important than the temperature, since the air temp, assuming the oven has been built to the proper specifications, should be relatively static in relation to dome and hearth temps.
Fast baking pizza ovens aren't really ovens, at least not in the sense of pre-heating an oven and having the hot convective air bake a cake. They're more along the lines of combo torches/hotplates. The hotplate/hearth gets pre-heated and stores all the heat for the undercrust, while the torch (flame + heat stored in dome) rains down IR from above. In this equation, air temp plays almost no role. Even the hearth pre-heats primarily via IR and conduction.
Instead of baking a cake, you're broiling and frying a cake.
If the floor and walls are all 900, it will be browned on top.
Do you mean the floor and non fire side wall? If the ceiling is 900 or the fire side wall is 900 you will not have proper browning on top.
Since air temp tends to be a bit of hassle to measure and fire temp is generally unmeasurable with typical IR thermometers, I converse in hearth temps and dome temps (and fire size/intensity). I generally don't pay much attention to wall temps because the fire wall and non fire wall will vary tremendously and because the dome temps and hearth temps should be enough to give you a good idea where the walls are at.