I have never seen it done this way, but why can't you use the truck's weight to help install a new coilover? This is actually a 2011 Raptor, but the process on a regular f150 should be the same. Why not bolt the bottom shock on the LCA, bolt the rubber and steel insulator to the shock bucket, then slide the coil spring on, align it to the bottom coil saddle, and jack up the A-arm until the top shock bolt pokes through the insulator? Seems easier, safer, and (especially with the weight of that 6.2 iron block); the truck isn't going to move.