IMO its down to personal preference mate (within reason!), how your suspension is set up can matter, as well as what tyres you're using and what you're using them for. I recently fitted some metzeler racetecs to my 'R' and jeeeeees i nerly fell off the inside edge of the first corner i went round. super fast tip in so i dropped the front pressure by about 3 psi from the recommended 36, and just left 42 in the rear. front felt an awful lot better being a bit softer as the profile wasnt as triangular resulting and a slightly slower but a lot more stable tip in point. Just have a feel on the road with the standard pressures (nice and easy) ... and if one end feels a bit hard and un-responsive just drop psi by one or 2 and try again.