First off, I've managed to print despite these issues. I think I may have tamed the z-motion, but the platform wobble may haunt me on future projects. The wobble is only bad on one side. If I adjust the guides to remove the wobble, the other side is too tight causing the gantry/platform to "stick and jump" rather than glide smoothly. It seem to be a linear change. In other words it less and less snug until there is noticeable wobble, or vice versa: more and more snug to the point of restricting movement. I've spent hours trying to adjust the guides, but wound up leaving them a little loose.
One thing I noticed is that the angle of the folded edges may not be uniform. If I place a straight-edge along the turned down face (the side that contacts the lower groove in the guide) I can see there is a gap. I'm not sure if this the cause or not, but it's my best guess. I accidentally delete the photo of it (it wasn't all that revealing anyways) ... but, if anyone thinks there may be some merit to this, I can try again.
Oh, and I did add some lube to the edges ... which helped significantly, but didn't fully resolve the issue.