1st year in the business and I love this site. You guys are the best source for info(thanks). Just bought my first commercial mower- 03' Exmark 52" ZTR Lazer Z hp 23hp w/435 hrs on it. My question is that in a prior post I saw the acres per hour productivity chart that eXmarks puts out w/the 100% & 80% efficiency rates per acre. I don't charge by the hour normally but am figuring $30-35 hour is the norm around here. How are you to judge the speed of your mower and at what speed do you run these with a collection system? Full,3/4 just don't know whats recommended.