Thanks, CZ. I hadn't thought about the cocking arms possibly being used to offset hinge pin/hook wear. Interesting idea. Have you seen how the mainsprings are positioned. They're a real bugger to get back in. I ended up using a three clamps; two to hold the springs in place and one to "slide" the cover plate back in place. I enjoy tinkering as well. I agree with your fertile minds comment. I think with the proliferation of electronics we're losing the "art" and "elegance" of a well executed mechanical design.
Phil