Summary

I replaced the plastic Y rod holders with metal ones ordered from China (from Funssor). The problem is, the 3 holders are the same but the one that holds the Y end stop is different. For a while, I left it in plastic but over time it does wear, so I wanted to use the metal holder and needed a different end stop holder. This is it.

A quick test showed that mounting it flat with the extrusion would not be workable with my bed (which is nonstandard). I wanted to put a slotted mounting hole at the radius so you could spin it, but I'm basically lazy so I put one hole in it and allow it to swivel on that bolt.That bolt will need to be longer because it passes through this part and the rod holder. I used washers to shim to a good height.

For the other side, I put a push in nut in the extrusion and an M5 bolt. This goes behind the piece and you slide it until it backstops the endstop holder and tighten. Not pretty but it works.