My base is way, way too flexible.  

I can get about 1 cm of variation in the end effector position just by lifting a corner.  This explains a lot about the issues I've been having.

My nice looking 1/2in oak faced plywood should have been my 3/4in plain Jane MDF apparently.

I have some new 3/4in MDF parked by the door, and this time I'm going to do two layers with cross beams.  I need to route out the cable holes through, which in my current 'borrowed shop' situation, requires tools I need to use outside.  

It's raining here in Montana, and has been for days.  MDF really doesn't like moisture.  I'll see if I have a window this weekend, although the forecast says Tuesday.  Wish me luck.

<EDIT> No luck, and now it's snowing.  So I have cleaned up/moved stuff around my borrowed outdoor wood working area so I should be able to get this cut tomorrow rain or shine, or more likely.. snow.</EDIT>