Tyre pressure is a function of axle load. It shouldn't matter what size tyre you run or wheel diameter.
If you run something outside the recommended tyres from the handbook start with the recommended pressures and monitor the wear, adjusting accordingly.
My diver always ran the tyres at the max pressure for best handling but then he didn't have to buy the tyres!
Inner shoulder wear due to camber may be due to the natural setting for the model. My RC will wear the inner shoulders on the rears, the geometry is as designed.
Centre wear will be due to over inflation, so reduce the pressures...