Blake explored a couple different designs for the pannier hooks, focusing on maximizing the amount of weight that the hooks would be able to support. We ultimately settled on this geometry, though without the additional lip on the end of the hook, which only increases manufacturing cost and adds nothing in terms of additional load capacity.
We haven't yet started talking to the factory about the pannier hooks. We want them to stay focused on finishing up the backrest prototype and begin manufacturing the backrests first. As soon as production of the backrests has begun, we'll start exploring the pannier hooks with the factory and get some feedback on the design and how much it will cost to make. We're hopeful that manufacturing for the backrests will begin sometime mid-March. If there aren't too many changes to the pannier hooks design specs, it's possible that we'll be able to start manufacturing the pannier hooks sometime in April or May!