your going to get lots of opinions on this. Your
oil pump question is something everyone who builds an engine has to deal with.
Oil pressure is dependant on
oil flow volume, and flow resistance. The latter is the most influental. It depends on oil viscosity, temp, and engine clearances.
engines need "enough" oil pressure to safely operate, but more than that is not necessarily better, and causes its own set of issues. Ford specifies 40# at hot 2000RPM, as a mininum.
To be succint, if you had reasonable oil pressure before, then i would suggest just replacing your oil pump with a stock Melling. If you have generous engine clearances, or run in a really hot environment, then a high volume pump may be indicted. Remember, if you have loose clearances, and your pump is pumping all the voume it can, changing the relief pressure spring will not increase your pressure.
You can of course tweak your pressure a few pounds with a higher viscosity oil, and run a high quailty low restriction oil filter, and avoid 90 degree oil line turns.
It seems to my observation that Stroked Windsors run lower pressures than the 302 motors, i think because of the longer rod stroke.
Don't worry much about your hot idle oil pressure, a no-load low rpm motor does not need much more than 15-20 psi to safely idle.
In summary, i would replace your pump with a stock pump, and if you run 45-50 psi hot at 2000 rpm, you are fine.