I am also currently making a strip quilt...my 1st one. I thought it would be easy-peasy, just straight sewing lines, right? NO! The least bit of deviance shows up on those long rows, everything gets off kilter, etc. No bowing yet, thank goodness. Probably because I did alternate my starting points like everyone one here has suggested. I'm just going to let it go a little wonky and put a funky, old fashioned label on it, so it looks like all that weirdness was intentional.