Jon,

You will surely hear conflicting opinions on this - but I used the roofing
stuff in my '90 and it worked great. I didn't get to the front doors before
I had an accident and bought my new bus - but I did due the back walls and
the ara under the rear seat.There was a big difference. I cannot say how it
compares to the real stuff (fat mat, etc.) but it worked for me. I forgot
the name of the stuff "New roof" or "easy roof" or something like that. Some
will warn of off gassing in hot weather - but I never experienced that
either - even in hot summer weather (although I live in the midwest so 90 -
100 is REALLY hot here.

As for placement I out it right on the back of the actual metal. Go Westy
has some good pictures of how they do this (with dyna mat I think) they do
not cover the entire panel - claim it's not necessary - but you can cover
the whole thing if you want.

As for speaker placement - well I have never used the bottom part of the
panel - I know folks do. The thing to consider is that the speakers will be
playing to your knees - however they also won't be blocked partially by the
side of the dash either. I am looking into speakers as well - and I think I
have decided to go with component speakers in the front- if that is your
choice I think the bottom part of the panel would be fine because you'll
have the tweeters mounted somewhere higher.

Again you'll hear varying opinions - but this is what my experience and
speaker research have shown me.

Good Luck!
--
Thanks,

Jeff
'85 GL (Gertie)
'90 Carat (Grover - the noble parts donor)
'86 (We call this one Scrap)
'78 Bus (Melissa) Patty's Bus