Just got the mounts in today. It wants to mount outside the grab bar and does not anticipate the rear rack being there instead.
A preliminary analysis suggests that I can Ignore the spacers, get slightly longer machine screws (8mm x 1.25mm. Two 90mm button top, two 80mm socket flat head) and set up the racks on the outside of the rear rack. This will be ugly but also will be quick and easy and will work.
Edit: two things won’t work:
Cutting space out of the rear rack spacers and squeezing the mount between the grab bar and rack won’t work. You need to cut 35mm out of rear rack and it only has 30mm to give, and even that requires cutting so close to the edge as to compromise a weld. You then need to stretch the rack out another 10mm to squeeze the mounting bracket in. Not sure if that is posible or not.
Per Pekingduck, below, I also tried to just remove the grab rail entirely. And squeeze the mount on the inside of the read rack. I needed to cut anout 25mm off the rear spacer and then shim the rest of it out with spacers. It looked good and fit great… but the rear mounting bolt on the rack blocks the c-bow from attaching to the bracket. Hmmm.
I’m guess first idea best idea. I’m ordering longer bolts.