adding zest to beer

I am making a wheat beer tonight and am going to add some orange zest. Question is, how much? I was thinking two normal size oranges worth.

Think I should put it in the end of the boil or secondary ferment it?

I made a holiday spiced ale this past winter. I added one whole large orange zest. It may be because of all the other spices i added but the orange is not very noticiable, but it is there. I added at about 3-5 minutes left in the boil.

I'm waiting for a beer I added orange zest to to condition right now. I added the zest of 2 sour/bitter oranges in the last minute of the boil. Samples tasted okay, but I wanted more for this beer, so I added the zest of two more for the last week (technically not secondary since I didn't transfer the beer, but the same idea). I soaked it in a small amount of vodka overnight and added the zest and the vodka to the beer. Tasted great at bottling, but it's a high gravity beer. If you're wheat is a "normal" gravity beer, you might want to only add it in secondary. That said, my beer isn't ready to drink yet so others may have better advice.

I added about 1.5 - 2 medium sized oranges to a summer wheat not too long ago. Added it just before the end of the boil. When I bottled a few weeks back it smelled sweet and full of citrus. The orange was quite noticeable. (A few stray peels made it to the fermenter when I splashed pouring through a strainer, but not many.)

Haven't tasted it yet, though. It's only just over a week in the bottle.