Sealant primarily seals for air penetration. Let's establish that.
No lab has ever, nor will likely ever, test such a nuance, so we can mentally spin this for years.
15 years ago, people used fiberglass instead of damping compound in a...
Curious, what is your attraction to this product? You've read above where it doesn't perform any better than fiberglass, cellulose, polyester or mineral wool?
Obviously I've missed a lot of dialog in tis thread. My apologies. You won't have success attempting to directly damp a beam. The dissimilarity with the stiffness of the beam and the drywall is way to large. Damping is optimized when ...
Just a point, that applicator being used is a "stock" gun with no modifications. I assume leather plungers, etc. Not at all optimized for Green Glue. Careful when you soak the gun in water overnight. The leather may swell.