The 108 nails is a new one. All you need is a sufficient number of layout points which will be connected using a long thin flexible wooden batten (some use a piece of PVC pipe) to scribe a line connecting the points. The batten is used because it will give you a smooth (also called "fair") curve. If your 108 points don't give you a fair curve it could effect the shape of your hull.
When using a power saw it is a good idea to saw wide of the mark and plane down to the line but it takes a well sharpened block plane to cut the end grain in the plywood.
I usually drill the holes as I stitch the panels. Some areas require only a few. Places where there is a lot of twist or bend in a panel may require many more to make the panel do what you want. What you are after, mainly, are smoothe graceful curves.
If you had a decent text on S&G building it should have covered all of this. The internet is not a a suitable replacement for a book with diagrams and pictures. My first build was a S&G kayak that was featured in a how-to book. Even tho' I had all the necessary details I still made a bunch of mistakes.

: Hey everyone,

: Last night I laid out the patterns and hammered in 108 finishing nails to
: trace the pattern onto the plywood. What next? Right now, I have the two
: panels clamped together. I would imagine it's a good idea to drill the
: stitching holes before cutting through both layers? If this is right,
: where do I make the holes? The pattern has crosses ~3/8" in from the
: edge every six inches, should the holes be drilled here?

: When cutting it out (I'm using a jigsaw) is it wise to leave a bit extra and
: plane the edge smooth?

: In the next day or two, the manual should be arriving, and these messages
: will slow down . Photos of the build so far will be coming very soon.