If youre after a more elegant solution (duh of course you are) the 'logo' rack by tubus is designed with heel clearance in mind, and no adaptors are required.
The only reason I didn't choose tubus, as the only model I believed that would have worked on my bike was the fly and the problem was that it could only hold up to 18kg, whilst the axiom could take up to 50kg, which would come in handy if I ever go touring and need to carry more stuff.
If youre after a more elegant solution (duh of course you are) the 'logo' rack by tubus is designed with heel clearance in mind, and no adaptors are required.