Driveshaft length?

[guywithuglyyota]

I am installing a duel t case this weekend. Front is a high pinion, rear is standard. I have zero lift and 33's. I am planning on lifting no more than three inches. How does 6 1/2 inches longer on the front and 6 1/2 shorter in the rear a good number to work with? The shop that is doing them says to factor in flex and all. Just wondering if anyone has a good number with a drivetrain close to mine. The tranny is an l-52 and 22r motor  Thanks


Luke