need help

ok so im having vibration when i drop the rear on my truck to drive it low. im thinking its my pinion angle. if my tranny point down 5, first drive shaft points down 4 degrees also and secont shaft points up 10 degress what should my pinion angle be?. its a two piece drive shaft by the way.

Do a web search on the subject, there is a very good article on 2 pc. drivelines on the Carcraft site(i believe) I had the link saved on my old computer before it crashed.