The aerohead is pretty damn light (QBP lists 405 grams) for someone your size. The thing to remeber about bicycle components is that they were designed for 140 lb racers who are (while stronger) are often much smoother than most of us. They ride frequently replaced bikes on smooth tracks or good roads. When they deal with crappy roads (Paris Roubaix, Flanders) you will see racers running 28c tubulars on 36 hole box section rims.
The additional weight of 8 spokes and nipples is negligible for non-racers and high spoke count wheels are stronger and easier to maintain (ever try taking a flat spot out of a vector pro?) One of the few justifications for folks to run low spoke count wheels is aerodynamics. Roadies pounding along in 53-12 can hit some very high speeds and the additional drag of a 36 spoke wheels really matters. In urban settings with low-ish street gearing much of my riding takes place between 15-25 mph where aerodynamics are not as important. If you are obsessed with weight, buy 14/15 spokes and run a 28 or 32 hole wheel up front, but at 185+ cargo, I would recomend a 36 hole Ma3, cr18, open pro, or fusion for the back.