If you want to use these strip strata without resewing (most accurate) cut the strata in the center (highest curved part of the bow). This will help "staighten most of the roll when you are piecing.
Just remember, gentle hands when sewing, and check for staightness every couple of cuts. (yes, I mean this) It is easy to get off and hard to get back on. If you are off, cut a compensating strip to even out your edge.