Anyone here used a Thule Xadapt kit for a bike roof rack, to change the standard "clamp around the crossbar" attachment to a track mount attachment? (Tracks like on an aero crossbar slot.)

Supposedly this Xadapt1 kit will do that for a 594 Sidearm rack and fit it to a Xsporter truck bed rack:

But based on the photos, I'm not sure how it attaches, and if it'll achieve what I want. Thule instructions I found online are useless.

I'd like to mount the Sidearm to the Xsporter rack as far out as possible, which is right above the Xsporter uprights, so the "clamp around the crossbar" mounts interfere with the uprights. If the Xadapt track adapter attaches the Sidearm solely using the track slots, then I can do it.