bowden drive to direct drive set up, but how do I configure it?

[Gordon Lin]

guys I posted the same thing in the hardware section but have had no help, maybe I posted it in the wrong place, so here it is again:

Voron 2.4, with Revo hot end, duet 6hc + 3hc + raspberry pi
latest unstable versions of firmware + dwc version
(sorry but I am away from my printer so I will post my config file first thing tomorrow if necessary)
all of my prints are single-color only (not into multi-color prints)
I like the Revo system very much and would like to stick with it
had multiple printers that were Bowden driven, switched to direct drive, and would never look back

Goal---to add the ability to print with second material (used for support) and remain direct drive.

I looked at the palette (too expensive, not reliable enough)
I looked at the ERCF (too finicky, too extreme)
I looked at the Prusa MMU2 (nope, just nope)

This here perfectly describes the solution:
https://forum.duet3d.com/topic/12939/dual-color-direct-drive-switching-extruder

when printing main material, direct drive motor is working in sync with Bowden motor 1 in push-pull
when printing support material, back up main material a certain amount, then direct drive motor is working in sync with Bowden motor 2 in push pull

Any help/pointers is much much appreciated. I am looking through the duet documentation but I haven't found anything yet. Maybe @dc42 can point me the right way to look?

PS:
this here also perfectly matches my need, but it is klipper:
https://github.com/HelgeKeck/rome

this here almost perfectly matches my need, also very interesting:
https://www.printables.com/model/436830-voron-stealthburner-taichi-bowden-assembly

[jay_s_uk]

@Gordon-Lin please don't double post. locking this one