I have been searching what to do with some Christmas panels and found this video from Missouri Star. Near the end, she shows a panel and has bordered it with pinwheel blocks, big ones and little ones. She said she makes the blocks she wants to use as a border, then measures that border, then cuts/trims the panel to match that measurement.
Don't know if this helps you or not as I didn't exactly understand how many of the panel squares you wanted to use in your runner. I would use one row of the squares and surround it with the pieced border blocks but not cut the panel until I had made the border. (She shows this method on the third panel near the end of the 7 min. video.)
Great Idea by the way and may work for one of the Christmas panels I am looking at now.
Murphy
https://www.youtube.com/watch?v=90jc09oVtdA