Thanks for the tip, toverly!
Getting a look at my modification ideas: I shortened the string block to 6 1/2, eliminating the point. Since I made my 9-p with constant fabrics, I put a 2" bar of whatever neutral I used in the 9-p between the shortened string block and the red bar, hoping this will make the churn dashedness more obvious. One of the things I didn't like in the reveal was the way the red overwhelmed the 9-p (which in my case are kind of delicate), so I got out my least solid reds and used those as the churn dash bars. I think the round sashing looks kind of comical, but I'm hoping a pale gray or black on white constant fabric in place of the strings will make the roundness less obvious. I have some pale gray yardage and a stripe, so will experiment with those.