Question....I am sewing the 'Disappearing Hourglass' quilt and on my blocks the white fabric is puckering. I am sewing batiks to white cotton and trying not to stretch it very much. When I get the first part done into the hourglass block, it irons out beautifully and with no puckers, but when I cut it into the 9 patch and sew that together I am getting puckers. I am learning not to be a perfectionist, but this is definitely trying my sewing capabilities!!

Help?