If money is an issue, try running straight 30 weight oil. It will bring your pressure up. If you has a lot of crud, could a piece of crud not have blocked the oil passage to the sender? I was thinking about this on another engine my friend has. I was thinking of removing the oil sending unit and have someone to hold a rag over the hole and start the engine up for a few seconds to flush out anything that could be blocking the hole.
90 YJ, 4.2 with 2150 carb 4.0 Head and headers, Nutter with TFI and MSD. 1" BL, 2.5" spring lift, 33", Goodrich KM Mud Tires. Dana 30 w Aussie, Ford 8.8 w LS. 9000lb HF Winch.