http://www.differentials.com/install.html

Found this too, but as I read I realized that I was all worried about 15 inch pounds on the nut, but the nut is supposed to be hella tight, its the rolling resistance that was mentioned way back there. It took me this long to get what that is. So I could have 200 ft/lbs on the nut and still have the right rolling on the pinion, got it now. I'll tighten it up some more and see how it goes.

 

Took you long enough for it to kick in!!!
Since you're now doing it the "fingers crossed way", the best I can tell you is to try and get the nut on by using as much force as it took to remove. Did you count how many grunts it took you to get the nut loose? Since you're going to be rebuilding the rearend, it's not going to hurt to drive the car for a while. If you still have a lot of slop after your nut is cranked, then that's what you had before you started messing with the thing. Ahhhhh, ignorance is bliss sometimes, eh? What you didn't know wasn't hurting you!

 

So I tightend my nut until the flange wiggle was only about a 1/8-1/4 inch front to back. Then took it and sprayed off the extra lube and it drove with no problem. There was a little whining at first, but that went away in a block. So I may have eyeballed it good enough. The side to side is the same as before.

Thanks for all the advice. I'll update this when the rear end falls out.