Thanks Jay!, this is good information.
I've also contacted Gary Chaplin in the UK, whose webpage inspired me to consider this idea, and yes I have contacted one of my engineers in Ontario to do analysis once the configuration is figured out.
Right now I'm thinking that the opening at the peak needs to be a bit bigger, so I will redo the rafters with that in mind soon.

Jay when you say "band beam" do you mean the plates?
I'm thinking the plates would be connected with threaded rod(x2?) which passes through the post to to the adjacent plate.