It appears your pix are not enlargeable when clicked on so it is hard to see any details in them.
Pixel sizes of 150x170 are too small to evaluate. From reviewing the available literature
it appears the axle ends are adjustable to length, ie telescope inside the down tube so as to adjust
to different wheel sizes, ie wheel radius from ~13 to 15" or so. FW axles are pretty much standard
in width so I think you just bend the axle tubing inward until it fits, no spacers needed. Spacers would
reduce the carrying capacity also. Origin8 seems to assume solid axle with some commenters
saying specifically that the rack is not meant for QR and Origin8 not for the newest through axle wheels
either. P clamps could probably be found or devised for direct mount to the fork.