Answer to question #2: The controls work great...just like the OEM controls when they were new (even easier!).  The cable convertors are easy to install and have only one small harness to route for the controls to the ECM.  I operational adjustments for infinite with the stepper motors operating the dampers (much more than cables).  Now, the downside.  Vintage Air only offers stepper motor technology in their GEN IV models (small and light).  I don't think VA offers stepper motors (and thus cable convertors) in their other boxes.  Traditional style under dash units and their other offerings do not have steppers (not in the pass unless they just introduced them)...always best to call Tech Support. 

The add-on, under dash style AC units do a good job and are the easiest to install...all the controls are in the unit.  I don't care for them because they can be shin knockers, they are heavy, old OEM units were designed for R12, and they double the blower motors, double the switches and harnesses and imped access to under dash service. 

One downside to converting the OEM HVAC controls to aftermarket steppers OR cables is you will need to remember where to set your levers or add your own labels to reflect temperature and damper settings for defrost, floor or dash modes.