[G0HZU_JMR]

I'd recommend making the resonator jig on a thin piece of copper sheet. It would have to be thin enough that you could still solder to it and also thin enough to bend one large corner up. Maybe choose something 0.4mm thick?
Any thicker than this and it will be difficult to solder to unless you have a powerful iron and a suitably large tip on it. Also wear safety glasses when soldering stuff like this as excess solder can splash up really easily.

I'd recommend putting the connectors and the caps and the inductor on one side of the sheet (at the corner of the bottom side) and have a drilled peep hole in the metal shim to allow a test point to your probe on the other side of the metal sheet.

The idea would be to be able to bring the probe close to the top of the resonator without causing any proximity effects to the high Q inductor. I'll see if I can put something together to show you what I mean.