Run the recommended tyre pressures shown for the car and then monitor the wear pattern over the first 30 to 100 miles; your NEW tyres will have a multitude of fraises on the tyre surface and the wear rate of these will tell you oh so much.
For example: on my RS3 (2-up and zero luggage) with 235/35 and/or 255/30 fronts and 235/35 rears I run 39psi front and 37psi rear: Audi recommend 41/39 but I found this gave far too much centre tread wear, on both front and rear tyres, and 'harsh' ride.
So start off with the standard for your car and monitor ALL 4-tyres while you still have the fraises...