coil spring sag ?

i've got a question about coil spring sag. ok, the coil springs on my 20-someting year old d100 2wd truck aren't broken, cut, or anything like that, but the frontend is now almost 4" lower than the rear (measured at the fender wall), i've already broken the plastic headlight adjusting screw retainers at least once or twice trying to get the headlights to illuminate more than a couple of feet in front of me. anotherwords the frontend it's really sagging. i'd also like to lift the frontend just enough to give it that 'level' 4x4 look. so my question is how much do coil springs generally settle over the years with normal use? just trying to figure out whether to order some custom springs with a 1.5", or 2"-2.5" over stock free height, in order to get me that level stance without over doing it. i do know that 2.5" is about the max lift you can make to the stock frontend without compromising the geometery and having to make other more expensive changes. also, how much of a factor would worn-out shocks be?
Author: michuy