I went 3/4" when I did my 5" lift which was sorta mismatched together. I had regular stock length Skyjacker lowers on and had rubbing on the fender. I called TopGun and they recommended the 3/4" for my application. Worked perfect...axle is exactly centered in wheel well...no rubbing even offroading or turning sharply into a inclined driveway. Give 'em a call....they are quite knowledgable...