There is plenty of information on setting up gears. I don't think gears are really hard to do. The hardest part is not saying that's good enough when you are just tired of trying different shim combos.
This, 1000%. Gears aren't really hard, if you know how to read mics and can understand some basic mechanics. Its just tedious and if you're impatient or a "good enough" kinda guy...you probably shouldn't do the job. I wouldn't try to do them laying on the ground. When I did my Jeep, I took the extra time to pull both the axles and get them up on a bench, so I was comfortable. I didn't want to fall into the trap of not wanting to check one more set-up, because I was tired of laying on the floor.
I'm contemplating doing the gears in my truck...but I'm not sure I want to go through the work of pulling the front differential on an IFS rig!