I did a 4ft by 2ft area. I drilled holes every three inches or so. You can individually check the vacuum of each hole you drill before you bag the area. If you can pull a strong vacuum the area immediately around the hole is pretty well isolated, so you may want to consider decreasing the hole spacing. If it won't pull much of a vacuum, then it is either in communication with other holes or there is a slight delamination, so you can increase the hole spacing.
I ran the pump each night after work until about 9pm and during the afternoons on weekends. The boat was on the hard for three months but it only took about three weeks to dry out the area I bagged. It started out really wet and ended up with about 4% moisture content (according to the moisture meter.) There's alot of humidity on the Texas Gulf coast, so I knew I couldn't rely on it drying out on it's own. My pump would only pull about one atmosphere of vacuum, and I know it would have taken less time with a more powerful pump.
I launched the boat last Tues, stepped the mast on Wed, and then placed 2nd and 3rd in our biggest regatta of the year Sat and Sun. Theres a lot to be said for a dry, fair hull. Good luck!
