Nice work Jules,
I did have a similar thought to you but my idea was to mount them off the pillion peg mounts where they connect to the bike frame and then run at the same angle of the bike frame, up towards the rear grab handles.

In about 6 months keep an eye out on those pop rivets.... depending how much weight is in your tool canisters will depend on how long the rivets and alloy brackets hold up to the vibes of the bike/road surfaces. If one or the other.. or both! fail on you just..... do the same thing but in flat bar steel and nylock nuts/bolts, weight gain is minimal but stronger.

Cheers
Reg.

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MY CURRENT RIDE: XT660Z T�N�R�
MY OLD RIDE: well you all know who she was