[Bob Putnam]

Ideally, the driveshaft and transmission axis should be parallel at ride height. Depending on how flexible your rear suspension bushings are, you might angle it down 1-2 degrees so that on accelleration it becomes parallel, but it's not that critical unless you've got very soft bushings.

It doesn't hurt to check for driveshaft u-joint bind at full jounce and droop...