I have installed the backplane in the original control cabinet.
It went together well. All that needs to be done as far as the major install is to build a cabinet extender to allow the door to close. 1.5" should be enough as a off the cuff guess but I can go 2" or 3" without any problems.
I was just able to run the spindle under cnc control. Very cool. Variable speed and FWD/REV work well. I had to use a 2.5 second delay on the deccel to prevent over voltage trip out.
Next step is to fit the encoders to modify the motors for encoders.