However you decide to classify them, vacuum bagged fiberglass laminates have a much higher fiber to resin ratio than a hand wetted ambient pressure cured layup. Vacuuming the layup does more than just hold the glass in place in that it also compresses the fibers together and reduces the resin volume (much more than you can accomplish with a squeegie). You can control the amount of compression and fiber/resin ratio by simply adjusting the amount of vacuum applied. For you doubters out there, next time you are near a vacuum bagged hull, tap on it with a knuckle and then tap on the hull of an ambient pressure cured boat. The vacuum bagged boat will sound like a steel drum - the other will make a dull thud.