I should be working on my regular work but SketchUp has an addictive hold on me at the moment. Trying to do a bit more complex roof line below. Immediately some things that pop out are the inherent complexities that occur when roof lines meet. The question is how to setup the plugin to automatically handle these situations, this will not be easy. I was able to easily trim and delete unnecessary rake and fascia boards as required. The trusses themselves need to be more dynamic so that one can adjust the overhang to zero as required. It is easy to select a number of component instances and make them unique and then adjust as required. In the second image I've copied an instance of the queen post truss to create a girder analog.
The other thing that needs some attention is the ability to easily create a valley set that frames over the larger roof line. I've got some ideas on this one, its going to take some interesting math but its not impossible.

