Hot oil pressure is a function of the oil viscosity, the volume of oil being pumped and the rate of "leakage" (clearances) throughout the engine. To increase pressure, increase the first two and/or decrease the last one.

Using 25W-50 oil with a standard volume oil pump and loose clearances is similar to using 10W-30 oil with a standard pump with tight clearances or 10W-30 oil with a high volume pump and loose clearances. Using a high volume pump with loose clearances will use a slight bit more power but not enough to be of any significance on a street engine.

There are several ways to accomplish the same goal.

Use of a high pressure relief spring doesn't affect the hot oil pressure at idle. Excessively high pressure on cold start should be avoided by using the right relief spring.