I once read on another forum a unique way to deal with the roof structure. The technique was used on a barn, but I don't see why it couldn't be adapted to a house. A group of Amish builders were building a large pole barn. They built the entire roof structure on the ground, sheathing and all, except for openings for four corner posts. The corner posts had hand-crank winches on each one, and they simply jacked the roof up into place. The rest of the wall structure was put into place, and the openings in the roof were closed and finished. I imagine you wouldn't want to jack it up on a windy day, and you'd want to get some diagonal bracing on the walls quickly, but I like the idea of roofing on the ground. If you slid off of the roof, all you'd get would be dirty.
your measurements would have to be dead on for that to work.
these days, you'll find some pros doing the building and roofing on the ground, and have it raised with a crane. It's done with trusses though.