Again I am building a cargo bike, and when I can I avoid drilling or welding the frame, and use existing possibilities like the Shockmount Bracket! This Bolt Frame is Parametric. As is it fits a chineese Forknow fatbike frame. Which has an asymetric triangular cutout in the metal brackets that connect the shock to the bike frame.

It is adjusted for 3 pieces M5 Bolts and the printed part should be fully under pressure. That means it should be clamped between two metal plates to which your cargo structure can be mounted. I use PETG for the printed part...