I've got one with narrow end caps that doesn't fill out the axle - bottom photo, so I recon I need a mk1 with wider end cap at the disc side - top photo.
I have a suggestion
I have some hope caps that are 20 mm to qr
If They were to be welded to my halo caps I think think it would work
15 £ the lot posted if you want to try
They will sit inside the 20 mm caps might not even have to weld them
