Good luck.....keep us up to date....we love our ICF home even though it was harder to build.

To cut cost you can use the screen grid block. We used it on our upper floor. Saves a third on concrete and the block we used is R30 compare to R21.

they call it hollow beam here -basically you order them to length and they span in one go --big hollow slabs and they sit on top of wall some pictures here showing hollow block flooring being used https://goo.gl/photos/VGwSdKommyaT5p8y5

I understand that the large crane that sets the hollow core planks requires 30 feet for the outriggers. Narrow lots do not have enough free space for the crane. Encroaching on the neighbor's lot requires permission. Another thing to keep in mind is that the HC planks can be used for the roof. Adding a thin slab on top of the planks can increase load carrying capacity. Plank companies that I have talked to want a curb (ledge) on the wall to keep roof planks from sliding down the slope. Some companies also want a curb even for a level floor. By the way, I specialize in alternative building systems. Almost anything except stick building. In most cases, I donate my time to interesting projects.