Thanks guys...to everyone who posted a response.
Frank, I'd be careful using the term "Yank". My boss is from Tennessee and you'd have a hard time seeing if you ever called him that:) The civil war still has echoes.
Before getting any responses to my question I went to Home Hardware and bought a roll of "Weatherstrip Rubber Seal" by WeatherShield. It was the only one that said "waterproof". After the postings by a few people today, I went online and compared prices and ended up ordering from Chesapeake Light Craft (as per Lennie's response). I bought a bunch of things...the Yakima foot brace mounting kit and adjustable footbraces, the "Creature Comfort Seat" (I'd love to hear from someone that has tried to mount this in a Night Heron..successful or not), and the foam hatch tape. Now that I know there is a canadian supplier I'll keep them in mind for another project (damn duty you pay on anything ordered in the US....silly if you ask me)
Does anyone know what the requirements are for a spray skirt? (tolerances?) I figured I'd go to an outdoor store with the yak on the roof and just convince them to let me bring a bunch out and see which one fits best. Can I just measure the circumference of my coaming and pick one based on that?
I'm pretty excited that I'll be joining the halves this weekend and then just worrying about sanding and varnishing for the next couple weeks and then....VOILA!, I'll be'a paddlin. All the details of customizing are still to come, but will be a fun chore. I want to wait until I use it a little to see where I want to put the extra rigging (rod holder, possibly a dig-video-cam holder, pack-holders, and my favorite...a beer holder:) Any comments or suggestions by anyone are welcome.
Now I must get back to the yak...trim the hatch lip and finish the coaming.

I have another question about a Sea-Flea (for another project), but I'll put it into a new post in case people don't scroll this far.
Adios,
James

: I had the same challenge. Live in Toronto. First ordered the foam from
: Chesapeake and ended up not using it because it was thicker than I wanted.
: Got my weather stripping at Home Depot. They have it in several
: thicknesses. What I used was 1/4 inch thick. Brand name is "Tago
: Weatherstripping". It is "closed cell" and has self
: adhesive backing. It is made in Canada (not that that matters but it means
: the Yanks probably can't buy the same stuff down south). Worked fine.