This probably isn't the best from a work/results standpoint, but it was interesting to make.

Belcrank mount.  Instead of a hunk of threaded rod to go between two plywood plates, it's a fitted aluminum pivot to go the same place.  O/A weight including fasteners is 1/4 oz.

And then I'm going to take this piece, which is probably overkill for top-level competition, and put it into a cruddy 25-sized profile sport/trainer.

Is the "Tom Morris" method the one that uses the threaded rod with nuts and a bushing?

That's kind of what I'm doing here, only with the aluminum axle instead of the steel all-thread rod.  It should be stiffer, and offer a larger bearing area on the plywood mounts top & bottom.