I wanted to make a simple, small dual-E3D mount for the Rigidbot. I used two E3D Lite6s which have been working flawlessly for me. They're spaced 24mm apart, but it took a little bit of tweaking to get it spot-on for me. I haven't had an issue with nozzle height. I used LM8LUU bearings in the slots, but it can also be used with the 3 LM8UU bearings that come with the Rigidbot.

The E3Ds are friction-fit into the holes, and they sit very firmly. The linear bearings are simply snapped into place. The single fan seemed to be sufficient to cool both hotends. Screw it into place like you would with the injection molded clip.