Just looking at the brake design, the truss tensioner appears to act directly on one of the fingers... is that correct? If so, I would think the design could be improved by adjusting that so the truss acted on the mounting plate for the fingers, and the fingers were shorter at the top and located against a raised ledge (either a machined step, or a piece of 10x10mm bar welded to the mount).
or am I overthinking it?