I found that I didn't like the motor adjustment very much on the MK3, and when I found this thing: https://www.thingiverse.com/thing:2990861
I realized that I no longer needed the motor adjustment. so I set out removing the adjustment screw hole, the square nut slot, I then made all the holes round and put them in the correct position, and while I was at it I decided to add the 4th screw hole. I believe if a motor manufacture puts 4 threaded holes in the housing then they should be used.
when printing this you may want to turn on supports, I did not and the part does bridge ok but it doesn't have a nice surface look to it. despite that the part is very strong and holds the motor in position in my mind better than the 3 screw with two slotted holes.
your favorite brand petg