oh man, I feel for ya! I did mine last year and it was NOT FUN!!! I used a floor jack and built a wood jig for the bottom so I could balance it on the jack. If I remember correctly, I think I lined up the side bolts first, and just put them in about a ¼ inch, just enough so they wouldn't flare the hole or pop out. Once you get those in, then go around and hand screw the rest in, making sure not to cross-thread that top bolt, as it seems to be the hardest one to get in! You may have to raise and lower the jack several times for each bolt to line up.
Overall, it took me 4 hours to remove the diff, and about 1½ hours to reinstall(damned road salt!)...
Look familiar???