That would help, but this particular connection is being "sucked
together", the DC is not trying to blow it apart. One should be
enough. That's all I have on mine, and my setup is identical to what
he is trying to do.

I use a five foot run of 6 inch flex tubing to connect the DC to the
main 6" trunk, which allows me to move it out of the way when I need
to get at my electrical service behind it, or whatever else I might
need to get at.

6 inch flex tubing on a five foot run should not create a large
impediment to air flow, but I wouldn't go any longer.

Joe



Back on the farm we sometimes put two or three clamps on a connection when
one wasn't enough.

-- Mark