Check with your engine builder for their input as 1 big consideration. Look at the dino VS
synthetic points related to your camshaft type, no synth. on a flat tappet cam unless it is a special blend with lots of additives-race only type.
Think about your area for max temp it will run. Use a
oil light enough to provide start up oiling but not so thin you loose pressure at hot idle to point of danger. You will of course see a pressure drop at hot idle but must not drop below 20 to 25 PSI for my tastes. Too thick and you bypass filtering on cold start up and risk bursting filters and so on. I always warm up my engine before loading it and zinging the throttle is a no no until temp is stable.
High
oil pressure is more old school that just gives HP away but I still lean that way, hell I am old so that's OK. I like to see 10 PSI for every 1K RPM with idle pressure of 30 or more ideal. It all depends on how the clearances in your engine were set up and what kind of cam and valve spring pressures you are running. I also try to avoid prolonged idle at same RPM. I burp throttle a couple hundred RPM if idle very long just to splash
oil all areas. I run a fairly larger solid roller cam and valve-train so low RPM oiling is not what everything else was designed for.
If engine is a bone stock cast iron donor ...... who cares what oil or type cause it was made to live a the worst the public can dish out.