MP3DP-Repeat Hub Variations

The MP3DP-Repeat 3D printer was released by V1 Engineering late 2021:
https://docs.v1engineering.com/mp3dp/

The center "Hub" of this CoreXY machine runs on a square rail.
It is designed to use a 20mm carbon fiber square tube.
That tube is not currently the easiest thing to source, so I have remixed it for two different alternate profiles:
1. 19mm square tube which is the actual size for 3/4" aluminum profile.
* The "trucks" that support the tube ends on the Y-Rails needed to be resized too and are included.
* 0.063" tube wall recommended
1. 2020 V-Slot compatible.
* The OD is 20mm, but the rollers had to move in to ride in the V-Slot.
* Only 3 rollers required.

On both Hubs, there are some "break throughs" at the screw counter-bores. I tried to cheat on the ID, but there was not much clearance to the tube to begin with. It doesn't appear to compromise the strength of the part.

Recommend 40% infill and 3 perimeters. No supports necessary - @Allted puts a lot of effort