I really like your template, it is very well thought out.
I have a friend that used to work in a quilt shop (and could do anything). She said you could use anything for a template,
a salad plate, dinner plate if large quilt and you want gentle
waves.
Though have always wanted to do this edge, I have always
hesitated because of the math. My friend said no matter what
size the block or number of blocks there is always something in the house to use. Your method proves the case very well.
I am going to save this forever. (I always forget methods I don't use for a while). Thank you, thank you.