I own about six full crossover guns, a dozen sighting devices for off eye shooting, and other lense blocking devices to help my off dominance. I am also scheduled for cataract surgery next week. When that is over, I will watch these videos with an open mind. By the way, all of these devices have been very helpful in my shotgun shooting.
Good luck with the surgery. I had it done 10 days ago. Went with nothing special for a lens and I'm very happy with it so far. Barrel sights are much better, and aperture iron sights are fantastic. I hope you do as well.