Drive shaft lengths

So I inatalled a sye and since I'm a cheap bastard I don't really want to buy a new drive shaft, I'd rather it's a zj junkyard one. I have a xlocked 231 behind an ax15 and an xj d44 on a 4.5 lift. It is 33.5in from yoke centerline to centerline at ride height. I have found that a 4.0 zj has a 32in front drive shaft when colapsed. So my questions are
1. without an easy way to test how much will the distance from yoke to yoke change under compression, I can easly measure at full droop?
2. About how much extension will I get from a 32in zj shaft?
3. How strong are zj front shafts when compared to tom woods or adams shafts?