When I built a strip canoe I made a jig that used a router to scarf the strips. The jig was just a piece of plywood about 3" wide with triangles nailed to the long side edges. Kind of like the old wooden miter boxes but with the sides decreasing in height at 1 in 8. I used a wedge setup to clamp the stips from the sides to hold them flat in the bottom of the box. Once the depth of the 1/2" router bit was set sliding the router base down the decreasing sides scarfed the strips with a couple passes. It was so exact in cutting the scarfs in the same spot relative to the box that it proved much easier to saw the double miter cuts at the bow and stearn on two separate strips and then splice the strips together at one of the station forms in between. One staple would hold the scarf together and also clamp it to the station form. I should get a digital camera.

Of course if you use stem pieces the strips would bet cut off after glueing. And all this exact length double miter cutting of strips goes away.

All this said, I think most people just butt the square-cut strips at a station form. Just be sure to stagger the joints, no matter what method you use, to keep the curves fair.