Any reason not to do roof mounted units? They can be ducted.
I have some real world data that might help predict loads and system needs. I have a dometic duo therm roof AC and heat pump. likely 15k BTU, 90% certain. If not that, 12.5k.
900W (3) of 60 cell panels mounted flat. Magnum PT100 MPPT charge controller. Magnum 2800W pure sine inverter / charger.
280Ah x 13.2V home grown battery.
Bus is fairly well insulated for a mobile vehicle. Good 3" of spray foam from Bluebird Wanderlodge RV factory.
85F ambient. Thermostat set to 73F. AC unit would get get down to temp quickly and then cycle maybe every five or ten minutes for a few minutes. Duty cycle approximately 30% to 50% for AC unit.
I was drawing NET between -120 and -160 DC amps. So with duty cycle, -50Ah to 80Ah per hour of AC use for -13F vs. ambient.
Each 300W panel puts out about 20 amps @ 13.2V DC in full mid-day sun.
Total DC load would then be 180A to 220A from the AC unit.
My Magnum inverter had no issue with compressor startup. My AC unit is stock, but I have on hand a heavy duty startup capacity to install.
So with twice as many panels, you'd probably still draw -60 and -100 amps @ 12V, but only when the unit is cycling, assuming similar capacity unit in terms of BTUs. You could pro-rate against 15k BTUs to determine the approximate draw.
If you are in HIGH ambients, your duty cycle on the AC unit would likely approach 100%. I was in 100F with hookup and AC runs pretty much non stop.
Hope this helps. #s might get you in the ballpark.
Doug