I used to cook pastries and tarts quite a bit, and one thing that always intrigued me was how recipes vary in their treatment of citrus. For instance, if you make a lemon tart, you can generally do the whole thing in one day and it'll set up just fine. An orange tart like tart a l'orange seems to require the filling to set for several hours longer.
Aside from obvious flavor differences between citrus fruits (lemons, limes, oranges, grapefruit, etc.) are there acidity or other variances that require different techniques to get basically the same results? If I used limes in lemon tart recipe, would I get a lime tart?
This link on Wikipedia wasn't all that helpful...