I've now modelled the 3d print that connect the two frame plates together, as well as modified the pressure plate to push the ball-chain around the load cell. 

The plan is to use 2mm dowels as locating pins and then glue the frame plates together. The frame connector also acts as a spacer for the PCB. For mounting Tetrinsic to something, the frame acts like a massive spacer between the load cell and attachment surface. To put it another way, the M3 bolts go through the mounting surface, then the frame connector (narrowly missing the ball-chain path) and finally screw into the tapped holes of the load cell.

Hopefully, the tension of the ball-chain keeps the load cell + pressure plate assembly somewhat fixed in place during assembly.