That's a great tutorial, and I would love to try it. I do have concerns....
I live in the South and 8 months out of the year, the temperature can easily be over 72 degrees. I know a lot of people are down on American buttercream (and yes I do put butter in mine), but to be honest, it's really the only alternative for super hot weather.
Also, I'm concerned about shelf life of a cake that isn't being covered with fondant.
I noticed a lot of people in the comments had problems with the icing deflating. Is this something that happens from time to time, or completely goes away with experience? I would hate to depend on a recipe that has off days.