I also assembled the acrylic frame. I had to use a certain batch of 3mm nuts to fit in the laser cuts, since the tolerances are very tight. One hole chipped when I pressed the nut in too hard. But it is neither a problem for assembly, nor very visible, so I think I'll be okay.
I printed the x-axis motor mount and idler holder and see if they fit. They did! so I printed a carriage and now the individual axis are movable!