My dealer set up the outside scalpwheels in the middle and the center in the top. I dropped the outers to mow at 1.5". I usually mow at 3" and my lawn is a little rough so your recommendation will probably work great.
I mowed my lawn in just over an hour for the first time. It usually takes 2 1/2. I think 1 hour is realistic once I get used to the mower.
My first impressions are; The Z910A is a little light on power for the PowerFlow, if I were a commercial user I would probably have at least a 925A with this option. For my use it should be fine as the cost to go to the 925 is almost $2,200 more.
The dump from seat bagger is awesome. It takes a little getting used to it hanging back there. You have to be careful not to bang it into trees and other obsticles. You definately have to have the weight kit with this. (my weights haven't come in yet, as the hopper fills up the front wheels start to get really light which is good because my bagger fill indicator isn't in either.)
Lifting the deck with the power flow on is definately harder. It may be an issue with my wife.
The cut quality compared to my old JD mower LTR180 is amazing. (I would expect this for the price)
I would invest in the suspension seat. It gives enough cushion to make the ride a little nicer. For the money spent on the mower $250 bucks is not that much. It's too bad JD doesn't just put them on all of the commercial Ztraks.
I was expecting a 2 Year warranty. When all the paperwork came through it is a 3 year with 1,500 hr which is nice.