I have the 1005 and 803 horns and have spent quality time with the 1505. The cells are all the same within each of these horns. The cells on the 803 are just bigger and longer. AFAIK, you can just scale the curves to whatever size you need.

I have heard the Synergy horn twice. They are very nice. I'm still hoping to hear them in direct comparison to my Altec system.