Rivet Nut Roof Rack

[eyebuzz]

Hello,

Looking to add roof rails and rack (I got a used one from a junkyard) to my 99 suburban. The vehicle did not come with any rails - just a bare roof.

Questions:

1. Is it advisable to use Rivet Nuts / Rivnuts type fasteners? From what I've seen online it looks like it would work -- but would they last or would they get loose over time?
   
2. If good on the rivnuts - how much weight (I guess it's really the aerodynamic-ness/resistence of what goes on the rack rather than weight) - so basically how strong are they? (This would be a full size suburban rack so it's got 8 points, and probably 16 bolts, to attach to the roof with - so plenty of distributed strength).
   
3. Also if good on rivet nuts - what type is the way to go - brand names, steel, aluminum, zinc...?
   
4. If Rivnuts is a BAD idea is it super hard to take the headliner out..or just a slow process?

Thanks. TT