I think everyone has a different way of doing this - I don't worry about squaring up before putting the two sections together - I just cut in half lengthwise then stitch the sides together....and for a shortcut (if your print is not directional or if you want a directional print to go two different directions) I fold the long piece in half lengthwise (make it half as long and the same width) then stitch down one side = wide enough seam to cut off the selvedge and still have your quarter inch seam - then use scissors to cut on the fold or a rotary cutter to cut off just the very edge of the fold....voila - you have one big piece. The back will eventually get squared up after the sandwich is quilted. Just make sure that the ends are not cut too wonky and it works for me.