Allow me to explain about max pressure.
The max pressure listed on the sidewall of tires should not be used for any purpose other then what it says - Max usage pressure. Do NOT refer to it when selecting usage pressure (except to say, don't exceed it). That's because tires behave basically the same way regardless of what the max pressure is imprinted on the sidewall - thusly:
For a given set of physical dimensions (size), the load carrying capacity vs inflation pressure is the same. You can see this in the load tables.
Yes, you will find SLIGHTLY different load tables for the same size, but that is because of a) differences between metric and English units, and b) different theories as to how tires work. Note: Tires work the same, but the formulae that are used to describe this behavior is SLIGHTLY different.
So Standard Load passenger car tires will always have a max pressure of 35, 44 or 51 psi, (41 or 50 psi for Extra Load), with the one exception being 36 psi for metric units.
HOWEVER, regardless of the max pressure, the load table is the same.
I go into much more detail here:
http://www.barrystiretech.com/loadtables.html
Tire wear vs inflation pressure:
First, tire wear is relatively insensitive to inflation pressure. Within a few psi of any value, the wear will be about the same.
Further, there are things that impact tire wear that have a greater effect. The most obvious is alignment - BUT - Steering tires tend to wear in the shoulders, while drive tires tend to wear in the center. This is very apparent in RWD cars, where the fronts and rears do different things. FWD cars, where the front tires do both, tend to wear evenly, but if they don't, it's because of alignment and/or the way the car is used (country driving vs city driving)