Working on a bid for a school campus. The grounds with the buildings is about 6 acres( buildings, beds, walks, etc). Then there is a newly purchase area that it wide open, its 4 acres. I use a z-spray and I'm working on my labor cost. I figured I could spray the entire 10 acres in about 3-3.25 hours. I would have to fill up twice. I'm guessing that spreding fert only would be about the same time. Am I close in your experience? Seems this will need to be prices at time + materials as I doubt that I could get my normal residential rate. Is $150 per hours in the ball park? I honestly don't have a clue on this.