Trying to get drywall installed as airtight as possible, and had a couple of questions. 1. Great Stuff makes a drywall gasket spray foam, but unfortunately it requires its own foam gun because it's water-based (can't use regular foam gun, which I have), and there doesn't seem to be a straw applicator version of this product. Instead, can I use polyurethane caulk (such as Loctite PL Premium construction adhesive), and apply it to the framing (top/bottom plates and studs) where the perimeter of each drywall piece will attach? 2. The wall framing isn't exactly flush (some of the studs are a little twisted). I was thinking 1/2" drywall would more easily flex and make a better seal against the framing than 5/8" drywall. Is this correct? If I can get just as good a seal with 5/8" drywall, I'd rather go with that for the extra little bit of insulation.

I need to install an under cabinet hood. [url]https://www.amazon.com/Broan-413023-Capable-Non-Ducted-Under-Cabinet/dp/B000UW20OM[/url] I'm going to close this hole and use a non-ducted hood primarily because the holes do not line up and I'd rather not get involved in more vent cutting. In order to seal this hole, can I cut the drywall in front of the vent (without cutting the vent) until I got to the studs to the left and right sides of the hole? If I cant get to the studs without cutting the vent, I was thinking of doing the following: [url]https://www.youtube.com/watch?v=TF8lr0KZNbk[/url] What do you guys think? Also, which drywall thickness should I use? Or do I simply just measure the existing drywall and buy the same?