Found a thread regarding these brackets:
I just mounted my Hepco & Becker C-Bow mounts to my new 2023 R3. I figured I'd share what they look like mounted to the bike for tribal knowledge. I'll create another thread for the boxes... Installation was not bad, just had to remove the mud guard from underneath and drill 4 holes for the...
There it says that you can't really load them up with weight because they are independent and probably sag, this is the impression I got. Thus, larger bags probably would be futile to have, as they may sag and rub on the tire, worst case scenario.
For now, I kind of think about this particular set up, have not made my mind, just thinking:
Top Box Set for Triumph Rocket III / Classic + Saddlebag TK3 | eBay It is for the III model, but I am sure it can be adapted to these brackets, just wondering how it will look.