I watched the exact same video and tried doing it with a rental reg set, with "standard" length hoses. I found that the primary hose and the octo hose got into each other's way if I wasn't careful. It was probably not actually entangled but it bothered me enough to not try it again. I only tried this once so I'm sure there's a way to make it work.
FWIW, I now have my own regs set up with the backup on the necklace (as shown in the video) and a 7' long hose for the primary. I also have a 40" hose for the primary, which is what is in that video, and that works great too.