All depends on use..
If your regularly loaded you need more in the rear..

My optima SW recommends 42psi rear loaded..

I run it at 34 psi all round..

Proceed 31 psi all round

 

In the UK there is a label stuck to the drivers door frame, I would assume that would be the same in other countries. I would set tyre pressures by what the label stated. I don't have a Ceed so my vote would be pointless, but the picture below shows what the tyre pressure label should look like.

 

Some of the op‘s observations depend on the tyre make, some have softer sidewalls than others and will appear flat compared to another tyre with very stiff sidewalls that support the cars weight differently?

 

My GT should be 33psi all round, but I run them at 34psi.

I like to have a bit of leeway should the temperature suddenly drop overnight, and as it is two of my tyres do lose a bit of pressure over the course of a week (I don't know if this is leaking valves or some corrosion in the alloys).

 

This is of course assuming the gauge you use is accurate!

 

Talking of tyres pressures...