[bpape]

Hi Anthony.

I'd do the 5/8 anyway. The 2 layers below will act as one if the glued it together so they'll have a different resonance anyway. Realistically, the difference between 1/2 and 5/8 for any resonance issues is far outweighed by the additional mass.

Just drizzle it as they show. It will spread out on it's own. Trust me, they tried it a bunch of different ways during testing and this is what Audio Alloy recommends.

Also remember that this may not be a full solution for your issues. There are other places where sound is leaking I'm sure. Think about doing your outlet boxes in putty before you do the new drywall too for example. Also, the Green Glue takes almost a full 30 days to really cure and become it's most effective.

Bryan