SRD - have you tried fixing it to the rack down stays...
I saw your post starting off this discussion and got one for my Helios. Had the same frustrating time trying to fix it around brakes and it not allowing the rear pedals to turn.
Had the brainwave that it doesn't need to fix to the frame as once the circle is complete that is the protection rather than the joining to the frame.
Have managed to get it on tonight - was a bit loose with just the 2 black fixings it came with so I've added some more cable ties.
I should be at the NY PY with mini HankChief if you want to take a look.
(Posting photos on here is beyond me -sorry)