In my humble opinion then,
Some factors to consider are where you measure. Sitting at rest you can measure between the upper A-arm and metal stop on the frame, then at full droop between the upper arm and metal stop on the frame. That distance can be lengthened by 1/2 inch with some mods.
Going up is determined by the compression of the "spring" or flexible variable rate compression bump stop or whatever you want to call it. When that is at full compression it just lifts the front end.
In all the lengthy posts on that when it was fresh on my mind I thought that inner measurement was about 3 inches or 3 1/2 if you extend shocks, lengthen anti-sway bar links and possible get tie rods that articulate more than 23 degrees to about 30.
That travel of course will translate to a bit more out at the end of the axle.