Thanks for the replies! Nice timing
Regarding the stiffness/weight ratio... If the brace needed to be stiff in all directions, I could see why that ratio would be important. However, the way I understand it, it only has to be stiff in one direction in order to counteract the torque from the bridge. So if I made a redwood or cedar brace a little taller, my intuition tells me that it would be stiffer (in the direction that matters) than a spruce brace of the same weight.
Anyway, what I think I am most curious about, is how the damping properties of the brace affects the vibrating top. Do anyone have any observations or speculations about that?
I think this stuff is really interesting, but I don't have much experience, so I really appreciate your input! =)
Thanks!
Sondre