Remix of the fantastic design: https://www.thingiverse.com/thing:6265603. 

Unfortunately the placement of the belt tensioner seems to be different on the N4+, so I have moved the hole. 

I've also extended the mount arm to allow for further placement of the camera, which is necessary with such a big bed. the original is just a bit too close to show enough of the print for me. Added extra support to keep the arm stable.