I assume the rough ridge you're referring to is the thick edge of one side of the tape. I had this with my Arctic Tern, and for my Outer Island ordered some tape from Raka that had a much flatter edge - nice stuff.

I would probably try a rounded scraper first on the accessible parts, just to knock off the sharp points, then try a Dremel as far as I could see. Getting all the way to the tips probably isn't necessary, because nothing will end up way down there anyway.

Another tip: don't inflate your float bags completely so that the skin is drum-tight, like a balloon. This will allow them some give, should they get pushed on by a sharp edge. Also, it will allow the air to expand a little if your kayak is out in the hot sun.

Dean