That's the difference in weight between the rim I ordered (Velocity Dyad) and the one my LBS actually has in stock (Mavic T520 aka, Mavic A719).

They were going to build the Dyad onto a Deore hub until someone realized that the Dyads they had in stock were 40h and I wanted a 36 spoke wheel.

Should I just let them build the wheel with the Mavic rim or go and order the Dyad?

And you can surmise too that since I'm having such a wheel built that I'm a pretty big guy myself. So would 75 grams make a difference?