Worst experience to date:

Gotta love the smell of gear oil in the morning!

On a 7.5 axle the proper fill level is 1 1/4 in below the top of the fill hole. I think an 8.8 is also ok a bit below the fill hole.

I use one of those cheap plastic pumps that screws onto the oil bottle. There may be easier ways, but this one does work.
 
I just bought another pump today while at the store. This one will go into the bottle and I can pump it into the rearend.

I changed my oil today and used the same oil pan I used to catch all the gear oil.....I still hadn't emptied it out.....needless to say I got the opportunity to relive the wretched smell again.