Why flatten the edge at all? Why not leave a bead (or cove) there?
Of course, you'd have to leave a mating edge (bead/cove) on the deck strip for when you join
deck-to-hull.

: I'm a convert to bead-up, having built a boat each way. Yes the
: cove is a convenient glue trough but it's easy to make a strip
: holder, run the glue, then flip the strip over. The advantage is
: that you can apply much more pressure to the bead than the
: fragile cove, either with tape/ clamps or both. If you're
: stapling, I guess it doesn't matter as much.

: Either way, I'd go ahead and flatten the botton of the sheer strip
: while you can hold the strip flat. A slight angle, 3 degrees or
: so, wouldn't hurt.
: The block plane will be fairly useless after the strip has a
: permanent curve so you'll have to removing the bead or cove with
: sandpaper.
: Eventually you'll probably sand both sheer strips at once with a
: fairing board when mating the deck and hull so the more wood off
: now, the better.