I will check on the uncompressed length today when I drop the trailer. I would guess 3". I have asked again for Anderson to provide the other answers you are requesting. At one time Anderson said compress 1/4 " or 120 ft lbs.
In my last conversation the rep basically said if it rides good go with it. The instructions pretty much say the same thing. The instructions show example drawings of good and bad scenarios showing drawings of sagging tongues, level truck and trailers, high tongues and saying " After hundreds of installations we have found that it is just as effective to basically "sight level" the tow vehicle and get it as close to level as you can by tightening /loosening the tension nuts. Trying to get the tow vehicle to be perfectly level is NOT necessary- you just don't want to be too extreme....we have illustrated some good and bad examples below."
There is no discussion of scaling (weighing) the finished installation or axle weights other that a warning to adjust loads or adjust tension to obtain level units.
Personally, I am super happy with the results and the way it drives. It looks like I am not going to be able to acheive total restoration of the front axle weights. I think that my last WD must have been horrible on distribution (even though all was level) based on the performance of this unit as seen / felt from the driver's seat.