Thank you Renny and jfitch. That is all very helpful information! I will ask the SSA directly. Maybe I'll ask them what class to enter while I'm at it: I could not find any information at all about class selection for a beginner on the SSA website.

And I do appreciate that many of the apps available that provide attitude info are not worth betting your health on. My concern is that all the instruments I'm considering have the option and don't appear to be "approved" by the SSA. As does the flight computer (XCSoar) I'm most comfortable with. That one is definitely a joke.