I've ghost played over paper before, and it did provide me with some good layout rules of thumb. Wound up printing about 4 control panels. Then I mounted in cardboard, and revised about 5 more times. Since you'll be playing longer when the controls are hooked up, cardboard catches a lot of things you miss. Consider the cp height, angle, wrist fatigue, and overall comfort playing as many different games as you can for a longer period of time. Nothing worse than a built cab that's uncomfortable for 75% of the games you'll want to play, even tho it's fine for the rest. Find a friend to help you "test" out the width, and at worst, measure how far your inside elbow will go with each stick vs. body placement of the other player. If you compensate for a cramped 2 player cp by angling your body, prepare to either be in pain after a while, or get ready for the idea of gettin' real cozy with your opponent.