http://gojeep.willyshotrod.com/ , has the correct pinion angle per the height of lift and using a angle finder you can get it dead on that is what i went by and worked awsome sitting at 5.5 inches of lift, here's the chart listed but theres a good write up here http://gojeep.willyshotrod.com/HowtoAlignment.htm
Diff degrees True Caster Hi Pinion True Caster Low Pinion
87.5 or 2.5---------6.5 ( 0-2" )------------- 9.5
87.0 or 3.0---------6.0 ( 3" lift )----------- 9.0
86.5 or 3.5---------5.5 ( 4" lift )----------- 8.5
86.0 or 4.0---------5.0 ( 5" lift )----------- 8.0
85.5 or 4.5---------4.5 ( 6" lift )----------- 7.5
85.0 or 5.0---------4.0-------------------- 7.0( 0"-2" )
84.5 or 5.5---------3.5-------------------- 6.5( 3" lift )
84.0 or 6.0 --------3.0-------------------- 6.0( 4" lift )
83.5 or 6.5 --------2.5-------------------- 5.5( 5" lift )
83.0 or 7.0---------2.0-------------------- 5.0
82.5 or 7.5---------1.5-------------------- 4.5
82.0 or 8.0---------1.0-------------------- 4
81.5 or 8.5---------0.5 ------------------- 3.5
81 or 9.0 ----------0.0-------------------- 3.0