I am bidding on a 20 acre capped landfill job and I was wondering if anyone uses an acre per hour rate. I generally charge $1 per minute based on the size of the deck on the machine. For instance a 72 inch deck I get $72 per hour to operate the machine. A 61 inch deck I get $61 dollars per hour. If anyone has an easier method of bidding by the acre please feel free to help me out!