What sound/heat deadener do you like?

In my 65 Bcuda I used the 40? 50? Mil Killmat under new ACC carpet w/o the mass/moss backing. Seems to muffle ambient road noise, but once the /6 and single exhaust is up to temp on a sunny day I get the feeling that mastic gets warm and radiates the heat throughout the floorboard. I’m no fool- I know darn well its a dark blue car with black interior in CA, so theres that…