Hi Don. you are almost there with your plank layout. Its not as complicated as it seems. You need to think two strakes at a time, not one at a time when it comes to top and but joins. . the outer edge of the two strakes together that are joined top and butt will be tapered but will not be angled. The outer taper for both is the same as if you were installing a single regular large tapered strake. the top and butt joins face each other making the difficult join between them and not on the outer edge. so in your plank layout above, all you need to do is make the outer edge of each pair more regular and a gentle taper. think of them as a single big fat strake instead of two strakes. Then the angled joins (top and but) can be done much easier. I try to make them as flat as i can so when the two angled faces come together they fit well together even if they are pulled into a taper. With the wale where I had the same top and butt joins the biggest problem i has was that i could not see the lines and had to get a felt pen to show up on the dark planks.