I had a couple of bad rod end bearings on my G2S, so wanted something to tide me over until replacements arrived.
These have a 6mm centre hole, and an M6 thread in the base, although all sizes are set exact with no tolerance, so you may need to file or tap some areas depending on the accuracy of your printer.
As regards extra parts, you'll need 2xM3 8mm screws, and I'd also recommend an M6 nut to use to lock the rod-end to the rod, as I don't know that threadlock would do the job here.
My copies were printed in PLA, and are a bit... creaky, but they do work, and I'd imagine lubrication or alternate material like nylon would cope fine.
0.2mm layers, 0.4mm nozzle
You'll probably want to flip the top section over, so that the support interface is on the outside of the bearing.
File and tap until you get the fit you prefer.
Lubrication is optional, but recommended.