Hi Gonzalo
With 40ft to play with i would put a center rail from front to back and hang them down the center fully rigged
if you`ve got a helper to get them down.
I find it easier to mount them on the wall,the F22 is now mounted with the undercarriage against the wall
on bike racks two big "L" shaped brackets with pipe insulation on them,you just have to make sure
the fuel is drained out,this does not distort the fus in anyway.

You have a nice big hangar there its got me thinking

brian