Castor for a 5" lift

What should my castor be at? Right now I have vibes and I think my castor is at around 11 degrees. Also how is the best way to figure it I have an angle finder and just put it on about three different places on the axle and came up with around 11 every time. (Yes I searched.)
thanks
As always Keep Diggin IT!
edit: I have about 5" of lift with Teraflex adjustable LCA's and stock uppers just FYI

http://www.naxja.org/forum/showthread.php?s=&threadid=6275&highlight=caster

Also how is the best way to figure it I have an angle finder and just put it on about three different places on the axle and came up with around 11 every time. (Yes I searched.)

Click to expand...

caster angle is measured from the lower ball jont to the upper ball joint on the steering knuckle. the vibration has more to do with the pinion angle. although caster and pinion angle are proportional to each other, as one changes the other will change.

read the link above and it should answer your questions