The Phoenix stations actually put a usable signal over your location, but the signals are weak, and you'll need a deep-fringe VHF-high-band plus UHF antenna to see them. Because the Phoenix stations lie in about a 30 degree different direction than the Tucson stations do, I believe that you'll need a rotator to turn the antenna towards South Mountain in Ahwatukee to get the best signal from them.
My suggestion would be to use a 2-antenna installation of a Winegard YA-1713 VHF high-band yagi plus an an AntennasDirect mounted on the same mast 4' above the YA-1713. Combine the signal from the two antennas using an AntennaCraft 10G221 high-input preamplifier, and use a rotator like a Channel Master 9521a or an AntennaCraft TDP-2 to turn the antenna array.
My personal preference would be to use the Channel Master 9521a rotator in your situation because it uses a remote control that will make it much easier for your wife to turn the antenna between the two sets of transmitters.
When mounting the power supply for the preamplifier, be sure that is it placed in the line between the antenna and the existing splitter so that the splitter does not cut off the DC signal from the power supply to the antenna-mounted preamplifier.
When you are finished with your installation, I believe that you'll find that the Phoenix stations should come in just fine, as will all the Tucson stations. Here is a link to a good antenna installation guide to help you:
http://manuals.solidsignal.com/AntInstallGuide.pdf