Sean M wrote:

Mikepier, you mention screwing the frame. Is it better to nail or to
screw the wall together?

-Sean

I meant if he is running a top plate, like a 2X4, it will be securely
fastened to the ceiling joists, whether he uses screws or nails. I
thought the OP was concerned about the integrity of the top plate if he
did not run it continuosly across the ceiling joists because of the
duct being in the way.