Hi Elliot,
I believe an added bent is but one option.
Another is to remove the oblique braces, and either use a Corbeling system and/or Truss System in concert with the Corbels. As such even a 100 mm square timber could suffice, and have seen similar with timbers as small as 75mm x 100mm when fashioned into a timber Truss Assembly...
I sent a PM as well to you with additional contact information...
Cheers,
j
Last edited by Jay White Cloud; 10/15/16 04:57 PM.