go thick or go home!
85w-140 in my moser 12 bolt w/ 4.11's and eaton hd posi and it doesnt make a sound. i've researched this quite a bit and it doesnt really matter which you use. some people seem to recommend using the heavier oil in maual cars, provides a little more support for the shock and makes things a bit quieter.
you will probably use a little over 2 quarts, i like to get a piece of rubber fuel line and slip it over the end of the bottle and plug the other end into the rear end. you can manipulate the bottle if you have a little hose on there to play with (
). you can hold the bottle damn near vertically with enough wiggling.