I too have had luck with blocking, including straightening a panel that was skewed so badly, that even the LQS suggested giving it up as a lost cause. I would start by measuring and marking the size needed on a flat surface. Lay down one side and tape the heck out of it. Then mist, stretch and tape down the opposite side. Then do the same with the last two sides. You may have to really wet down some of the shrunken areas, to get them to stretch enough but it CAN be done! Good luck!