Sage,

I asked almost this same question and got a response from Rob: http://www.kayakforum.com/cgi-bin/Building/index.cgi?read=44124
I would just point out from reading your post the difference between a 1/8" "gap" (one thats an "even" 1/8" all the way along) and a "gap" that "varies" in thickness by an 1/8" up and down along th way. I made my gap 1/8 of an inch and worked to get it as "even" as I could, think that will save me troubles and work later.

Arthur