Some more progress on my build. Third picture is the final pump mount set up. The other pictures are of welding the oil tank which I designed to fit inside the 3PH. I put in a good size baffle in the center to split the intake and return to insure the oil gets homogenized to help control temperature. There is a port in the tank for a thermometer to monitor temp.
The second picture is welding the 10-32 tabs in place for the fill/vent, which was all for nothing as you will see coming up.
I always pressure test tanks with air and soapy water, and when it comes to plugging the holes, anything and everything that works is the rule.
Tank capacity is 27 gallons filled to the top. Prince recommends a 25 gallon reservoir for the pump that I have, so I'm good there.