Have you noticed the lenght of the turnbuckles, they are all the same lenght. Those are not the real heavy duty ones and if you were to put long ones on the ones in the center would break, thus the reason for taller plate bosses toward the center!..
OK...I got that part, but dosen't that put a bending moment on the plate bosses? Lot of stress on the hardware holding the plate pads to the plate. Dosen't look cosher to me...at least not from the pic. Can't really tell, though.
Thanks GF.