The Co-Motion Speedster is a steel frame. Compared to the C'dale it has the same cranks (Gossamer) but Rolf disc brake wheels vs Mavic Cosmic Elite rim brake wheels on the C'dale. Ultegra gears vs Campag Record (10sp). Wound up carbon fork vs Reynolds carbon tandem fork.
The C'dale is around 2 kg lighter and also a stiffer frame. As said previously the Co-Mo seems to handle better.
They are both the same length in the back (72cm).
I am sure Co-Motion could make a frame as stiff and strong as you want and also give you a bit more BB height to clear those 200mm cranks.
BTW we are only a very average sized team at around 320 lb.