I redid this because the original one didn't fit my printer for a mm in the z axis (the arms should be 7.25 with a gap of 12mm and they were off).
The design is using the same system (so I'm keeping the plate and screw that I had already printed from elfco's version and discarding the arms that didn't fit) and mixed it with the original that came in the printer in Illustrator.

After printing I olnly had to remove the raft (the one created in MatterControl only needed a snap...it was awesome and really smooth) and it fit perfectly.

ADVICE: some people have trouble with the screw and plate which where designed by elfco, so they recommend to scale on the X and Y the screw to make it smaller but not on the Z.
As aforementioned, I didn't have any issue with his screw and plate, only had to screw and unscrew a few times to losen it a little