You guys spend way too much time worrying about, and practicing stuff, that will never happen to you. Until recently, we scoffed at backup masks on all but the most extreme of dives as being unrealistic and carrying unneeded gear. I carry one now but still feel stupid doing it. In thousands of dives, never once have I had to deal with a lost mask. While you should know what to do if you do lose a mask, focus on the aspects of your diving where improvement will have a more tangible benefit.