Double curved shape with quad elements.

Hello there, 

Currently I am looking for some details and manufacturers who can produce double curved canopy shape using quad elements. There is maximum 15mm different between the neighbour quads, so I believe it is subdivided enough to apply rectangles.  

What not clear is the joining between the mullion and transom, a T or X joint between the elements. Sometimes curtain wall manufacturers use welding for steel, sometimes just a "click" joint between the transom and mullion for usual structure, I mean for straight, vertical facades but in this case I have no idea how to construct double curved structural members.   

I attached an example file If someone could help.

Thanks