This has been such a long thread I can't recall everything.
Was the idea of just hard wiring the high speed fan directly to "compressor on", thus giving the comp the high speed fan at all times?

you need to vote in a party that will stand up to the EPA. right now they are unrestrained, and can do as they please
no other solution

LOL

Already did
At some point you won't be able to get it at all.
We should have learned our lesson on R12

On second thought, try to get a shot that is more perpendicular to the pipe, ie not at an angle. There is a possibility that if you were wrenching on the hex, perhaps THAT is the schrader adapter, and the barrel shaped part unscrews separately off that. Am I seeing a PN on the switch body? Go around...

Agree it does not appear to have enough depth to the fitting on the pipe to include a schrader fitting. Once someone recovers/recharges, before they recharge, there are adapters available that could be installed to provide a schrader base. Tim, the site owner, may have something available, doubt it ...

From what you describe unfortunately we have to assume there is no schrader. An unfortunate way to build something. We assume the part got very cold when the port was hissing, indicating refrigerant was flashing.
Are you able to post a pic or 2 so we might get a better idea of the construction

Good job. Good luck. Keep us posted. Have a nice Holiday
Texas Dave

yes. Pull from the low side only

Without the depressor it is not useable " and open the high side valve on gauge?" If by this you mean open the high side handwheel on your MGS, then no. That will not accomplish anything. As JohnHere states, the vacuum in the system will suck the oil into the system. You don't need the MGS...