[FC] Interior Panel insulation

[corvanatics@corvair.org]

I know I read about this before.  I just looked through the archives and found 
nothing.  I can see the insulation through the rear air vents has fallen off 
and is covering the vents.  I have been trying to remove the rear panels and 
almost have it.  I have stripped most of the screw heads and have to deal with 
getting them out.  I think I know how to remove the passenger side panel but 
the drivers side is being a pain.  I have removed all the bolts and can wiggle 
it but it won't come loose.  I am in the process of taking off the front 
interior panel to see if this will help.
Now about the insulation.  If I remember correctly it was suggested to use a 
spry type of insulation, that way it will never fall down again.  I was 
thinking just some 3M undercoating stuff unless there is a specific sound 
deadening meterial available.  Speaking of noise, what part of the car does 
everyone think is the loundest?  The engine compartment area or the road noise 
through the panels?  both are loud now in my FC so I can't tell.
I also have a bunch of dynomat and was thinking of laying it down somewhere 
and would like to put it in the loudest area.
Thanks for your suggestions,
Harry