standard 7 hooked in - that's all very well for those who have a middle appendage that can touch the deck of the board for extra support, but happens to the rest of us?
About that Video, Andy now ride with 30 Inches if not longer line, after he tried 30 inches he put a guy on 24, than 26, 28 and 30 with a GPS. Same day, same wind, same sail and board he was faster and faster and from the 28 to 30,the speed jumped quite a lot when passed to 28 to 30.
All that that to say, if you have a modern board, you should use a modern stand(board shorter..so have to be stand more straight and have a higher boom) and according to that 28 to 30's inches long line. I'M 5'10 (177), I'M using 30 inches, when I tried them for the first time(passed from 26 to 30), the first thing who stroked me the most was how easy to open the sails when gust comes in a non planning mode, not even have to unhook. Also, can go upwind sooo much better.
Good luck!
Nord_roi