Looks like the old post tabs for the interior trim can be used to mount a piec of angle and then do a cross member that way it's not hanging too low on you and a machine shop should be able to get that bend correctly for you also. I'm enjoying keeping track and making me thinking about doing the same. I might leave the lower trim in the back though just for astetic purposes and to keep it a little factory but I like the headliner idea. I would try to get it close to the roofline as possible so the reflective material wouldn't fall far. That or mask everything off and use undercoating on it to help shield some of the heat.