I dont know the answer off hand, i would contact GG directly. I would also verify that GG is applicable for use on strips between bays, when adding mass to an existing basement ceiling. Ive only ever seen data for Full Sheets of drywall.

As far as sealant, you can use a standard non hardening caulking like 100% silicone, or Butyl caulking. This is equally effective as any brand name 'acoustical sealant' and often much lower priced.