I would just run it off a switched 12v source like most everyone else does.. unless of course there's some mandate for you to connect it through the oil pressure switch. I run the p4070s on a car with a direct 12v, and on a truck just wired into an under hood switched 12v source. Those are very low amp draw pumps and don't even need a relay.
that mandate would be called safety. With a switched 12V the pump will continue to run in an accident potentially pumping gas into a fire. By using the oil pressure switch the pump will not run without the engine running. In the case of an accident that doesn't stop the engine the pump will feed the engine and it will run without pump gas out in the the environment. If it does pump it out into the environment then the engine stops running, no oil pressure, pump shuts off.
But go ahead and do it your way.
