Best weather stripping?

Hello, There is an un-insulated cavity where my garage addition attaches to the house. It runs the height of the wall and is about 4" deep by 4" wide. Visualize a very long box. Looking at the top of the box, it's 4" x 4". The box is around 9' long. Along the edge of the "box" there is a slit about 1/2". I could easily fit the tube of canned spray foam in there, but I think I'd use a huge amount of the foam. The slit is not quite large enough to allow me to stuff fiberglass or Roxul insulation in there. I was wondering if cellulose insulation would work. Is there a "project sized" kit available for cellulose? Any suggestions? Thanks in advance.

I have a outside door to seal but I want something that compresses easy so the door will close easy. Do I choose a foam tape that says "maximum" compession that would compress easy ? Thanks and God bless.