just the spacer in the front. no need for rear. even with a load in the rear the truck sat strait. so i did not even bother with the add a leaf! are you running the 5.5 block in rear or the 4 inch ? here's a couple pics of a load in the back prolly around 1200 lbs.
2011 f150 fx4 blue flame 6.5 bed. 6" bds lift with 2" leveling kit. fox shocks 18" cepek torque rims 37/13.50/18 micky's atz's