You are right on, on replacing the control box for $100.00. Thanks for the info on this. That will likely be my option as I will probably skip the add a zone.
As for the flow rates, I have no idea what they are. Combinding zone 1 with 2, I would only be adding two 4" spray heads. To me it is kind of stupid that they made two valves for that in the first place.
I really like my nelson controller box. Its a good piece of hardware.
Thank you very much for your help.