I received the specifications direct from FL yesterday. The post I reposted was very close. 10 inches front + or - 1/4 inch, 9 1/2 rear + or - 1/4 inch is the correct specification for my chassis.
For what it is worth, my front was a full inch too high and the rear was 1/2 inch too high. The instructions FL sent me did not specify which to do first, front or rear. Since the rears have an adjustment valve/mechanism on both sides I did those first. I got the rears spot on. The fronts only have one valve/mechanism. My fronts are now set at 9 7/8 right and 10 1/8 left. I figure if you do the fronts then the rears, any adjustment in the rear could throw off one of the fronts. In actuality, I adjusted rear, then front, then rear again and then measured front again to find no adjustment needed that time.
PS If you do this, be very careful. It is not hard or any more dangerous that doing other things UNDER your rig. I aired up and put the jacks down to within 1/2 inch of the ground all the way around and also placed two heavy duty jack stands under the frame rails. I did make several trips up top to readjust the jacks following an air valve adjustment.