Oberon make two types - one is more expensive and has adjustable in the name. If these are those ones I’ll take them.
The grub screws are a coarse, loose fit and need to be done up super tight to stop them coming loose and being lost, along with much of the mirror assembly. Wrap the thread in ptfe tape to improve matters
There’s ptfe tape already on them - just dab some thread lock on too after you found the position you want them in. They never once came loose in my home with just loctite on though to be fair