I'm from the same area. Concrete slab with rebar footers, columns and tie beam. All tied together. Metal straps holding down the trusses (roof). Shed: Concrete slab with "L" shape threaded anchors placed in the raw concrete at perimeter, bolt walling to anchors and strap frame. Strap wall to trusses (roof). I do use screws and nails on the trusses, but nail the 5/8 sheeting to the trusses. Not sure, but I think the reason that they say, not to use screws is if you ever need to replace the sheeting it will be difficult to remove. I do agree with the post, not to follow with a "T" on any forums, but they give some good paths to approach. Put a couple together and you may find the answer you are looking for. I would like to think that we are all here to help one another with their projects.