Citrus

If I may ask a few questions:

  1. How much zest do you use?
  2. Does it matter if it is orange, lemon or lime?
  3. At what point in the brewing process do you introduce the zest, and for how long?
  4. This is probably a dumb question, but here goes anyway: Is there any way to use orange juice? I can produce gallons of the stuff in season. Can I ferment it directly? Can I make orange wine or some sort of
    liquor? Can I add it to already-brewed beers to make some sort of shandy (and what’s the process for that)?