Hi Alan - It certainly would have been easier to do this in the design stage - if you intend to notch the frames for the stringers. Carlson's Hull Designer program (aka Hulls) works well with chine construction. It's free.

If you don't intend to notch the frames, it will be easier. I think you'll need to have the hull upside down, in any case. I, personally, would use at least 3 stringers per side for a boat this wide - or more if your stringers are less than Tom's standard 1"x3/4". I'd place a set near the waterline (or at least at the sharpest turn of the bilge), and I'd place the others equidistant between that one and the keel and the gunwale. With the hull upside down, you can eyeball it - right side up will be a problem. Lash the stringers in place, or mark their final positions on the frames, then cut notches for them and fasten to your taste. BTW, if a straight edge, set across parallel stringers, can contact the frames, then that will be a bulge in your skin. Adjust (or add) stringers to prevent this.

This is a wholly unscientific way to do it, but it works. Check out Robert Morris' book "Building Skin on Frame Boats" for more info.
I've built a SOF canoe (traditional) and a SOF rowboat (yost style). There weren't any guidelines, but they turned out well.

Good luck!
Dave Gentry

I used two stringer per side for the rowboat, but it is narrower than your canoe, and there's still a lot of unsupported fabric between the keel and the first stringer (it's fine, though). Here's a pic: