Experience with Dynamat for cowl insulation?

[Dakota]

I know Dynamat is more for sound than heat.   My accumulated parts pile does not include the insulation pad for the cowl area above the heater box. I have leftover Dynamat. Am I better off for minimizing heat from the engine with the Dynamat or going with the stock insulation pad?   The frequent $20-30 purchases I've made lately for all the "little" things I need are adding up, so I'm wondering if I can maybe avoid another purchase.  The stock pad is the one pictured below.

[70 Challenger Lover]

When I was reassembling my RT recently, I found myself asking the same question since all those little things do add up.

I did use the correct fiberglass insulation with the cardboard backing on the vertical surface of the firewall because I wanted the plastic nails to poke through into the engine compartment and maintain the correct look. On the other areas though above the heater box and inside the hinge pillars, I used a thick type of jute padding I had leftover from when I did my rear seat. A while back, I purchased a roll of thick heavy 1/2" padding from a local fabric store pretty cheap and it worked beautifully to provide a layer of protection all around the metal seat frames front and back. Basically like the original material I found in the seats. I had a bunch left over so I trimmed it nicely to fit underneath the cowl areas and glued it in. Came out nice and saved me a couple dollars.

I think dynamat May also work nice if you have a bunch left over.