I tried this today with 5" sqs, worked out beautifully, the centre join was spot on, but the bias outside edges bothered me as how the blocks would behave in a quilt. I then took some yardage and lined up the 45 deg line on the ruler with the lengthwise grain and cut sqs, then sewed as before. This worked well to and I got 2 sides with lw grain and 2 with width wise grain. Would use more fabric but be more stable IMHO.