Rumblefish, your questions are all good but no one knows. lol. Well, someone knows but.....
The funny thing about oil pressure is the more you provide, the more you leak.
Although I will be running a HV oil pump on my R3 engine, I have put together lots and lots of engines with standard volume pumps running standard pressures....nothing 'higher' than stock. And with stock volume pans. What I have done is restrict oil in some places and ensured the oil passages - all of them - are smooth and generous right up to the point of restriction. I want the orifice I installed limiting the oil, no place else. I'm also a big believer in baffling where needed, and in crank scrapers and one-way, Teflon coated windage screens, I don't believe in windage trays.