More work done, I have a proper spoil board now, 3/4 MDF. I tell ya, wrestling a sheet of that around single handed used to be easier in my youth! Notice I did the magic tape trick for my x servo wiring. Dust collection and router power will hang from above.
I took two 1.5" strips off the sheet and made cheater rails for the inside of my wheels ala @jeffeb3. I took one side and made sure it was straight by clamping it to a long level then air nailed it down, then butted the wheels up against it and went to the other side and worked my way down the table fastening the second strip as I rolled the gantry down the table. Easy peasy and no more wandering, but now I have to raise my belt mounts by 3/4" and redo my endstops and the squaring. That should be much easier the second time.
I also printed the 4" duct collector fitting system designed by @tailslide and shown in this thread. That is one fine piece of design work Greg! It was a 25 hour print and I wasn’t sure I was going to get the supports off it but managed eventually, only cutting myself once. 
