Mario
Your system looks adequate mechanically, It’s possible that the previous guy used two regulators because he had one apart and noted how small the feed hole is in these regulators.
Electrically you need to drive the pump with an adequately sized wiring and a relay.
You can use the switch to control the relay I also would use a Holley oil pressure safety switch that way when you shut of the ignition the pump dies as well. And finally pay attention to the grounding of the pump the body and / or the chassis are not always the best way to ground things with a high amperage draw.
