Best Gasket Adhesive for Cyl Head Cover Gasket?

Yep, Yota Black is the best, use sparingly.
They make orange also for use with ATF fluid and gear oil. Black is for oil or coolant.

 

Unfortunately, Yes

 

For something like that i'd just use a little grease in a few spots, clean it up well after mounting to avoid it "melting" and running everywhere later. Any sealant is going to take a while to setup enough to do anything meaningful, unless you're fine with that.

 

This stuff is hands down the best but no matter what I do if I buy the compressed can style it dries up and won't come out. I end up stabbing through the seal or whatever and the can then unloads all it's glory.