Once upon a time
I needed fittings which could couple with the bmw auto tranny stock fittings, for a remote cooler. I went all over the place, even to a special hydraulics shop. None of them could get me anything.
as for the Water temperature and oil temperature stuff, remove a bolt from the system, or a sensor, and take it with you, so you can compare threads.
Best of luck, let us know how it goes, I wanna get some gauges myself..