Thank you for the offer to contact you directly. I found I am limited to 420 characters! Biggest issue is if I use 1/4" lattice strips to get the backer board over the flange, I have that much to deal with on the matchup to the drywall on one side. Seems like a lot. If you go above the flange, doesn't the moisture barrier do the same thing as being over the flange with the backer board?