I am not sure I understood about doubling-up the ridge beam and placing 2x4s under it, but I do plan to install 2x4s that run from the underside the end rafters to the tops of the side walls to provide a nailing surface for the siding. I imagine this would help keep the ridge 'up' and the walls from sprading under load. I was planning on NOT having any framing members directly under the ridge, so that I could easily install a gable vent in the center of the gable walls.