I didn't watch the video but when I made a rope starter for the opposed twin on my GTR 4 zero, I welded a small bead around the notch for the rope because the edge of it tends to fray the cord after while. For emergency use it probably wouldn't be much of an issue but at least the edge should be smoothed off a bit with no sharp edges.
Better have a good starting engine for rope starting. It works but it's very annoying and slow to re-wrap the rope every time. Pretty much all small engines prior to the mid 1950's had rope start from the factory.