I spent today getting a bicep and tricep workout in the garage. I had seven cherry boards to flatten, each about 7 inches wide and 36 inches long. Several of the boards had substantial twist to them and all of them had some cupping and bowing.
Making this process even harder is the lack of a good workholding solution on my bench for working faces. I settled on a 3-point plan of holding boards. Two screws at the lefthand side of the bench and a notched batten at the back. This seemed to work alright, though I broke the heads off of two screws over the course of my seven boards.
Next I need to sort the boards to decide what parts come from each board and run them through my thickness planer (!) to get to appropriate final sizes.