Driveline Angles 101 or Everything you ever wanted to know about driveshafts but were afraid to ask.

I went through this dilemma when I had to get a driveshaft to account for my O/D trans and slightly moved engine/trans location. So much differing info/opinions since most people seem to build based on hard launch/drag racing principles.
Tremec has a great downloadable app to use, though how to hold your phone when it has buttons on both sides so they don't affect your readings was a little tricky.

EDIT: Tremec-as mentioned in the article, if I had bothered to read it first.