Tronxy X5 not-so-Mega gantry (Y carriage)

Inspired by Graham01's Mega Gantry - but I designed mine from scratch, so I haven't attributed it as a remix - hope that is OK.

I'm using the direct extruder conversion by Kozamaker, but I didn't want to use the suggested three-wheel carriages as they were no larger than the original Tronxy-supplied metal plates. The Mega Gantry carriages were too wide for this application, as were the remixed Semi-mega Gantry - so I designed some that are longer than the originals, yet ensure the full print