I have a hardware that gets installed on industrial doors.
It is always the same parts, sometimes in a LH config, sometimes in a RH config.

The door sizes will also change, but this does not change what is in the kit, only how far from each other the parts are.

I want to have an approved assy for the kit, but I also want that kit to be flexible (doesn't need to move, just the size and handedness as mentioned) when inserted into another assy.

The kit has about around 100 parts. It may be inserted into a higher level assy 100 times, so making it "flexible" doesn't really make sense, as it's already one of our slowest large assys.