3 things that help me with keeping strip sets straight: (1) always set the seam; (2) PRESS, don't iron; and (3) I lay the strip sets crosswise on the ironing board, so I'm only pressing a small section of the set at one time, then gently move it along. I found that when I laid them out lengthwise on the ironing board I always ended up with the strip set having a bow or curve, and then sub-cutting it is a mess. I actually think that a strip set with three or more strips is easier to keep straight than one with only two strips...