The pressure within the bearings comes from hydrodynamic pressurization; look it up.
Pressure at the pump/ filter/ oil gallery only assures that there is oil available for the bearings to inhale and pressurize, i.e., the pump is supplying oil faster than it can flow out of the bearings. Any positive number should be acceptable. Customary minimum numbers are basically safety factors. Increasing the oil pressure, e.g. by shimming the relief valve spring, just makes the pump work harder and put more heat in the oil, for no defensible reason, as far as the crank and cam bearings are concerned.
There are other reasons why you might want more flow, i.e. to force more oil out of the various orifices and squirters that cool the bottom of the piston crown, or lubricate the piston skirts, or spray oil on the cam lobes, etc.
Stock systems are normally adequate, within the normal stock rpm range. If you are running your engine faster than stock, you might consider modifications to the oil system, but which mods are needed for competition depends on the specifics of the particular engine.
The simplest and cheapest way to find out what your engine needs is to find the people who are doing well with that engine and not blowing up, ask them what they did to the oil system, and do just that.
Mike Halloran
Pembroke Pines, FL, USA