In beaurocratic limbo
Join Date: Mar 2006
Location: Los Angeles, CA
Bikes: Specialized Allez, K2 Razorback
Either will work with you, especially with such a bomproof rim, but I think the 3X will only be 5-10 grams more than 2X considering it's just the drive side. At your weight, though, you could get away with far less spokes, so do what you like. I was your weight when I was a teen, and all of my wheels were overbuilt for me, including 28h 2x rear/radial front with Deep V rims.
"Well, I guess you can cut the arts as much as you want... Sooner or later, these kids aren't going to have anything to read or write about." (Richard Dreyfus as Glenn Holland)