I am not sure if you have intact does, bucks, or both, but guards work really well for me.. for the most part. If a buck is trying his best to spray out of the cage, he will usually succeed regardless of what is in his way, but they do contain most of the splashes from all of my gang. I have one doe that somehow always gets past the guards and her tray, but she is an oddity among the ladies. I have taped a plastic barrier up behind the stackers and along the floor to catch anything the guards miss. I wipe it down with a vinegar/water wash about once monthly to keep it clean.
Best of luck!
Lauren