I haven't checked what's in my hood, but you may be right to avoid felt. It would tend to retain moisture and promote rust, unless it was impregnated with oil or tar. My hood isn't really very accessible right now, but I can try and check.
In my cab at the center top between inner and outer rear panels was a piece of rubber foam material, serving essentially the same purpose of reducing vibration.
Your link doesn't say how thick that sound deadening material is.

Last edited by klhansen; 08/02/2020 7:16 PM.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.