KB, I just sailed through there last Thur, and I believe the video was taken E to W. The mangroves/land on the right in the beginning of the clip is Madeira Pt, I believe, and the narrow part at the end is where you start by going between the S end of Big Key and a small island just below.
There was a section in the middle, not evident from this video, where the markers seemed to me to have a big gap. Certainly at night you would think so. I sailed straight E from where I lost the markers for a few minutes then spotted them with binos starting up to the ENE near the tip of Madeira Pt.
I liked the route for the scenery and maybe it would be good for a paddler, because there is some land in some of those islands if you needed an emergency stop. It's not much use to a sailor in a challenge because it runs E-W for a long way and is extremely shallow in places. If you can sail E that long, you don't need to to leave the standard route, which I believe would be slightly faster. I could be wrong on that.