My building board is 6 foot long by 20 inches wide. It sits on a bench that is a bit bigger though so I have room for wrenches and stuff, Can't have enough stuff!! I also have three drawers and three cabinets under it so everything is close to hand. If I had a bigger shop that U shape would be a good way to go. I haven't had any problems building planes 1/4 scale and smaller but I did have to widen my board this year by a few inches for a wing.