I agree with Capt Bruce.
For what it''s worth, I''m currently redoing my settee cushions which entails sewing in #5 zippers. If you sew them in by lining up the outside edge with the fabric edge and then fold the fabric back over the zipper you can top stitch the material down without being very close to the zipper teeth. So you don''t need a zipper foot for #5 zippers either. I HAVE a zipper foot but don''t need it!
Don Casey shows how to do this in his book "Canvaswork and Sail Repair".