I decided to target the prototype for iOS 7.
Currently there is way too much fragmentation in the Android market. Below infographic shows how Android devices are fragmentated.
And below infographic shows how operating system versions are fragmented.
And below shows how screen sizes are fragmented in the Android market.
I just don't have the budget, money, or time to account for all those variations. And having to debug issues for all those screen sizes and operating system versions would jack up the development cost.
Since Apple is coming out with iOS 7 right when our prototype is going to be done, I'm going to focus on iOS 7 and do some debugging for iOS 6 before launching.