After lots of fooling around getting the printed dimensions just so, here's the first real revision of the carriage replacement.  The old ones have worn the plating off the 2020 rail in places - a really bad thing. :)

The flag might get shorter, if there's room in the chassis for the carriage to go higher.

The print is in carbon fiber nylon, from 3DXTech.  Only one nozzle clog so far... :)