someone once asked me, what's the favorite upgrade. I would like to say that Di2 is my favorite, but if you gave me one choice, i wouldn't let go of my wheels go. They can be moved to other bikes and when you roll on a nice set, damn.. you do less work!
Good luck there, and update with a picture.
I'll file the invoice under G(arbage).
50mm even better
I have the 24mm carbon tubulars (not a fan of tubulars), but they are so damn light, i had to give them a try. LEnt him to my buddy who does climbs all the time and he loves them. Me, I prefer the flats.