Hi Nick,
to be honest, I do not know, as said, I have opened in both forums to “open an official request” for collaboration 
I am aware about the rclone server webdav, I already made a lot of attempts, however, I ended up opening a bug with duplicacy (please, take a look here https://forum.duplicacy.com/t/rclone-webdav-storage-path-test-does-not-exist/1821) as looks like they do now work well with the rclone webdav implementation (or rclone implementation does not work well with duplicacy webdav client 
)
If at least webdav could work sharing files to rclone, it’s better than nothing. Of course is always better a “direct serve”.
Thank a lot for your reply and the time to consider such collaboration.