[TR] seats

[Gary Nafziger]

List,
I'm beginning to work on my seats (tr-3) and am planning on doing a
plywood seat bottom covered with foam.  I remember reading other listers
mentioning they'd done the same thing.  When i measure the seat bottoms I get
approximately 7" height on the front of the seat bottom and around 4" at the
rear.  Did those who built plywood ones make them tapered like that?  Also how
much foam did they use to cover the top?  How firm was that foam?  I'd like a
firm feel but not wanting to "feel" plywood hardness under the foam. 

I've
found one foam seller on the internet but attempting to figure out which size
and which firmness has been challenging.  I've also been told that automotive
seat foam is much different than normal apholstery foam.

Just wondering what
others have used.

thanks!

gary n.