Bidding on a 20,000sqft buiding for final cleaning, Has large lobby 5 offices 3 meeting rooms, large kitchen, 5 warehouse size roms with roll up doors, 2 large public bathrooms and 2 smaller bathrooms, 22 windows on side of building and 5 interior glass windows. There is carpet, VCT, 8000 sqft of concrete floor that have to be cleaned for painter to seal and ceramic tile. Would I make more money by charging by the hour or by the square foot and how much per square foot and how much per hour?