There is a rotozip bit that is designed for this. The tip has no side cutting action so it can guide around plastic electrical boxes without chewing them up so bad. Be sure that the wires are tucked in nice and deep in the boxes.
The pros that did my house didn't even meaure a lot of the boxes or maybe only measured in one direction from the edge of the sheet. Eye-ball guestimated the location, plunged into the center, found the inner edge, jumped over to the outside and went around the outside.
They did use some nails, but only a couple per sheet to hold it up until they could put the screws in.
Their procedure was: Measure and cut the sheet for length (and width if necessary). Measure the stud locations and mark. Start two or three nails on the upper edge of the sheet at the stud locations. Lift the sheet against the wall and hold it there with one hand while reaching up and hammering the nails with the other. After the sheet was in place, zip in all the screws with an auto-depth drywall driver. They used corded drills and didn't stop spinning them, even to put the screws on the bits.
For the walls, they put the 12' sheets horizontally. They did the top sheet first to get it tight to the ceiling.
They did the windows in a similar fashion - nailed the rock up loosely over the window, zipped around the outside, and then screwed it down tight to the wall.
- Rick
