I am building a few sets with these same components, and my calculations and measurements do indeed call for different lengths for drive and non-drive side(.7 mm). However, as Im getting spokes by the box, and they are 50 bucks a pop, Im just using the same lengths for both sides. In my opinion it will make absolutely no difference at all. Your first mile of riding on the wheels will affect relative spoke tension more than a .7 mm difference in spoke length.

By the way, for a 3-cross wheel with H.F. D.A.'s and deep-V's, you need 281's.