About the removing of the pla is very simple, only remove a little of pla (sending) on the spots at red in the image. But you will only gain at the most haft of millimeter, no more..
so if you have 1 or 2 mm of gap, this will not correct your problem. I used this trick only to have a better contact of the 608 with the tubes, but i already have contact before doing this.
It appears you have printed several pla piece in different sizes, i think this was an bad move. This will introduce possible geometry problem that are very difficult to solve. In my opinion the best you have to do is to print again to have all at the same scale.
I still finishing my own z axis, i hope not have any problem.
I printing the rigid version, man… that an great piece of engineering!! Really appreciate the work done on this. I ready the cnc won the thingiverse competition. I receive an email to put my printer on the same competition, but the printer is nothing compared with the work done with this cnc.
Well done Vicious, you have skills.. You need to create an 3d printer.