This is why I love my EZ angle ruler. If you need the setting trangle to line up with a block that is 6.5" unfinished, you cut a strip at 6.5" wide. Then you use the angle to subcut it. Since it has the "dog ear" at the top already gone, you're cutting a larger HST than you'd get if you went point to point.
Yes, doing this way you will end up with the bias on the outer edge, but to date, that has never caused me a bit of problems.