I just tested WhateverGreen with Mojave public beta 2. The artifacts seemed to start showing much faster, but seemed slightly less intrusive for some things. Previously when the artifacts would appear, the menubar text and drop down menus would be unreadable, but so far that hasn't been the case with WhateverGreen. The artifacts aren't staying on the menubar permanently, but they do seem to be permanent on the drop down menus. I can watch a fullscreen youtube video in Safari without artifacts (although they do show up while the video is switching to fullscreen). I only tested for maybe 15 minutes so it's possible that it could get worse. For me, any amount of artifacts is unacceptable so I wasn't interested in testing any further.