I looked at the case, I had similar thoughts, but I would have holes for the coax cables to connect to the NanoVna and also an extention to mount
whatever test board you are using, in my case the SDRKits test pcb.
Would seem pretty easy to drill holes for the cables to come out, then mount your protective case on another longer board to have a place to mount the test fixture.
Hope that adds some ideas.
Mikek
