After putting the 60" MMM on my B7500 today (it was easier than I thought it would be for the first time thanks to all of your threads) I can't remember what tractor RPM I should be mowing at. I can't find anything in the manual. I started at 2000 rpm but that seemed slow. I then remebered that last year I mowed with an RPM of about 2500. It shows the PTO 540 at this mark. Is this the correct engine RPM to run while mowing? TIA.