Adding Fluker provides multiple scenarios. FLuker at LG and Lance Louis or Carimi at RG.
I don't see James Brown being anything more than a backup....maybe with potential at LT too. But we really didn't get to see him much in 2012, so he could improve.
And in 4 years you when Bushrod is 33 you could move Webb back to LT (he'd be 28) and Fluker could go to RT.