From what I remember
@Blue85 posting up years ago, the 7 piston is still smaller than the R4. That, combined with the cycling switch controlling it, there is no concern for the pressure in a properly functioning system.
You could add a high side cut-off switch, as was introduced in the GMT400 systems, it would just need a port to tap the switch into the high side.
The best way I have seen to test for leaks is using nitrogen and soapy water, but it's still difficult to have bubbles show at the compressor shaft seal, in my experience. And you need the evaporator case opened up to check it with bubbles.