Just saw this
You are right on the valve.
Design flow is 15 and psi max should be 1800.
Suggest finding two qty small gear pumps that can handle 4000 rpm and flow about 7 gpm at that speed most all pumps can handle the 1800 psi.
Run a 10 gal resevoir.
Find a cooler that can handle 15 gpm and run it on the return side low pressure, research the junkyard volvo cooler.
Look for a control valve that has a built in relief or run a 1800 psi relief before the valve and return the dumped oil to tank.
Tee both pumps together.
Use 3/4 suction per pump and 1/2 off the tee to the valve and motor.
Try to use o-ring boss or jic, stay away from pipe on valve, pump and releif.
Find a high spot to mount the tank under the hood and mount the motors low as possible or look at the pto and a bed mounted tank. Don't plan on running your steering off this system at least for now.
Reply with questions.