Rear Sag ?

I have decided I need to fix the rear sag on my 2000 XJ. I have taken your wisdom into account and I am going to do a add-A-Leaf in the rear and a small spacer or new coils up front. My question is If I have 1.5" of saga from front to rear. From the floor to the bottom edge of the fender front is 31.5" and the rear is 30". When I do the add-a-leaf does a 2.5" add-a-leaf add a net lift height of 2.5 or is it a gross lift height. Thus

Net
for rear would be Current 30.0" after 32.5"

or
Gross
for rear would be current 30.0" after 31.5"

I am trying to decide if what size of front spacer or coil springs I would need to purchase so the XJ sets pretty level.

Thanks