I was reading a blog and the woman was talking about making scrappy strip quilts....her specialty....you know the ones where you cut all the fabrics by width of fabric and just arrange them in rows. She said the way she conquers the bowing of the strips is by sewing the strips by twos....and then sewing the 2-strip sections together...and then the 8-strip sections. Apparently she says that by having 2 strips sewn, it stabilizes the fabric and you don't have to do that right to left and left to right sewing. It's worth a shot.