Hi all. I am new to woodworking and have been watching David Charlesworth Lie Nielsen videos on precision planing. I think I want to adopt his technique for flattening boards, but I am confused on one point. In his videos he uses a Starrett 386-24 steel straight edge. This 24” straight edge works great in his video, but the board he is flattening is less than 24” long. So I figured he probably has longer straight edges he uses for longer boards. So I bought his books and he only recommends a 24” starrett 386 straight edge. So my question is how does he use his precision planing technique on boards longer than his straight edge? Anyone use his technique?

Thanks for any advice you can give!