To find your best fuel pressure your gonna need to put your baby on a dyno

To tune your fuel pressure at the track you need to crank your fuel pressure up until you notice your trap speeds drop at the track

I personally just set it by ear, take the factory recommended setting & add 2 psi or so & drive the car then play with it and just feel out the performance from change to change you make etc...

Your really want to tune your fuel via a management system such as a afc controller or hondata.
A fuel regulator baisically adjusts wide open throttle fuel pressure.
Hence the need for a fuel controller & dyno.