I would have to research. Not sure if routing the supply (violet) line to a single line will work. You could always give it a shot.
Where in Arizona are you at? I would be willing to help you do the full vacuum connector replacement procedure, and then you would be good to go. I have done it on mine and I think we could have it done in about half an hour.
EDIT: After some further thinking, I am not sure, but I think that the only other item controlled by the vacuum connector would be fresh or recirculated air. Also, if the supply tube is connected directly to the "center vent" tube, you may no "off" so air would always be coming out of the center vents (not a real issue this time of year, though, here in Phoenix....lol)
EDIT #2: When it gets cooler out, we could also change the airmix door actuator, so you have full control of your air and heat. Will take a couple of hours, but I work cheap