I've been fine with 14 days fermenting big ipa's, but you can go 3 weeks, then dry hopping for a week. I never get past a couple days in the bottle, because I get anxious, and it always tastes so good. 2-3 weeks if you can really wait, but whats the fun in that!??
Citra is a nice hop, for my first ipa, i used it with amarillo, simcoe, and centennial.. talk about tropical!