Air Mover Calculations - How Many Air Movers Do You Need? 

Great question. It comes down to surface area. If you remove all the drywall and the studs are wet to the ceiling. The wall area would be the same. If, however, after removing the drywall only the bottom 3 feet of the studs are wet, that would be the amount of surface area you would calculate for that wall. As a side note when dealing with an open stud wall, it can be helpful to use Layflat ducting, and or plastic sheeting to direct the airflow to where you need it.