Cat 5P5005 adaptor replacement

I'm trying to figure out if I can use standard hydraulic fittings instead of the Cat 5P5005 adaptor and M5317 and some other Cat parts to hook up a gauge for setting the servo compensator pressure on the piston pump in my Cat 931C loader. The gauge itself shouldn't be an issue. Has anyone done this with common fittings, or do you really need the OEM parts?

All the hydraulic fittings should be standard ones, you just need to figure out what you've got.

That's what I thought, but since he got it working we're not going to sweat it.