Wood is the best isolator material.
Heck, at one time, someone - maybe Mr Gasket? - sold an asbestos gasket stack. That ain't gonna happen again!
As far as a heat shield, the best I've used is a GM one; IIRC its application was for a Holley on early Z/28.
Works great under a Holley on a BB Mopar, or anything else for that matter.
I don't know if the architecture of an AVS would benefit as much, being that the bowls are on the sides vs fore & aft.