I've never found that they need gluing, if you use the correct drill size.
We make test jigs by using a spare blank PCB attached to the top of a plastic junction box, then drilling out the component holes where appropriate for test pins, through the board and box.
The wiring, power supply etc. fit inside the box.
We also add some plastic toggle clamps to hold the board being tested to the rig, if it has mains power on it or testing takes a significant time.
If you cannot get the test probes a good enough fit, I'd just add a tiny amount of bostik or similar contact adhesive on the back of the panel and rotate the test probe to give a bead all the way around.
That will prevent it moving, but you can still peel that off easily enough if you need to change the probe - they can get damaged quite easily. With a stronger adhesive you may wreck things trying to change one.