Gee .. I would like to say something too .. to help, not sound bossy either.
I certainly am not a know it all, and I have never taken a class. But... I read everthing I can get my hands on.
I do it the same as gcathie does. Measure across the center, cut the strips that size, pin the center and the ends and then in between. Then if one side is a little more fabric than the other of the pinned seamline I make the adjustment needed by putting the side with the extra fabric (baggy pants) to the feed dogs. It will bring it in to the shorter side and this way I avoid pulling. Oh, I use a stelleto to help guide the top fabric too.
If all else fails, I just say oh it is terrible fabric. Yeah, that's it .. I blame the fabric! :twisted: