Spool Holder for Modular Shelving Unit

I had made up some smaller brackets to mount on the inside of the shelving unit some time ago (included) but decided I would like the spool to sit outside due to convenience.
I tested with 2 clips and it seemed more than strong enough with the frame bending before the bracket suffered any noticeable effects. The cut out is to allow it to fit over the shelf which protrude but it doesn't require it to be placed over the shelf section.
The brackets could also be mounted to the inside of the shelving unit.
There is around 130mm space to the centre point of the PVC pipe I used (35mm OD). There is no reason smaller diameter pipe would not work.

I found 3 perimeters and 30% infill made them strong enough to store 3 or 4 spools if I needed too (tested but not used with multiple spools mounted). Supports will be needed for the pegs allow I did have the supports break on one print and even though the peg looked a little wonky to start with once cleaned up it worked fine.