My comment about it not working was specific to using the EVA carriage system. Excessively customizing that design to fit with the R2 defeats the purpose of a universal printhead system. I still have no doubt the 8mm carriage rods and accompanying bearing blocks are entirely possible though. Your mockup does deviate significantly from what I've been planning though. I had planned to use shorter carriage rods that could be installed without drilling a hole in the side of the shell. Similar to the ultimaker design that inspired this, I intended the carriage rods to be planar to the gantry bushing and would be clamped in place.