I have previously owned a local brand 4 bike rack, while it was nicely overengineered in most places, it ended up bouncing around a lot and I sold it. I now have the Thule Velo compact 3 with the 4th bike adapter. I like it because once you get to your destination it folds to fit in the boot easily.
A couple of hints once you have worked out how to get a 26", 2x650b and a 29" all in place, take a photo for future reference???? and set some time aside before leaving to do this. I use a pool noodles to fit between bikes to stop rack rash and if you going off road use an old inner tube to hold things together a bit tighter.
Good luck
