Structural Engineer for Storage Building Plans

Looking to get stamped plans for a 50x30 storage building with 16' ceilings and a loft on one end. A portion of the foundation is below grade. No utilities will be included. I'm looking to reduce concrete footprint requirements by back filling with up to 2' of gravel under the slab to reduce the unbalanced backfill. This should improve the cantilever and bring us to just outside code requirements. The loft section of the building will be built to the NC-IRC standard unless you require it as part of your calculations or specs. I plan to buy trusses from a truss company so they will stamp the roof design unless you require input. 4:12 pitch at 30' span will be a pretty standard truss.