You don't actually need to have the Sun Harvester Shield to use the latest version of the program, and it would probably be better to stick with the newer version. Here is the about how the Sun Harvester Shield is wired together. http://www.cerebralmeltdown.com/wp-content/uploads//2012/07/SunTrackerCircuit3_bb.pdf
The only component on the shield that you absolutely must have is the RTC (Real Time Clock), everything else generally just makes life easier.
I would have to know your location roughly to be able to answer most of your questions easily.
3 though is yes, the altitude is zero when on the horizon.
Hope that helps,