I think that a licensed engineer is the most qualified person to design structural elements. There may be some cases where a manufacturer (like trusses for example) have technicians that design their own system.
If you need that service I can work with any engineer you choose.
Usually the only time required on my part is sending a CAD file to them.
Here are some local structural engineers:
Gessner Engineering 680-8840
Dunham Engineering 599-5430
Dudley Engineering 666-0942
For good details there are several guides available these days:
This shows how to brace a house properly to handle higher winds and tornados
Also these days we tend to have more and larger windows and doors and so portal framing is important:
For the basics of building codes I like