I was having a few problems with the Z smooth rod sometimes being pulled/shaken out from my Hictop Prusa I3 during a print, which was allowing the X assembly to shake which would ultimately end up ruining prints.
I decided to design this part which securely hold the M8 rod with a screw which clamps the part to the rod and connects to the motor mounts with existing screw holes.
I wrote a small blog post about this at https://mkdev.co.uk/z-rod-support-hictop-prusa/
I used 100% infill to ensure the part was super strong, However I'd recommend at minimum 70%
This was designed using tinkercad.