I tried the dominatrix for half a season and liked the setup. But wanted to create something on my own, so took the base principles of the tactic, and made my own variant. The formation is kinda different aswell. Have had decent success. But did not touch the corner tactics. So it was set on default.
I think you have found the formula of how to conceed very, very few goals Langvatn, with the three central midfielders and one defensive.
My tactic is however not as successful as yours obviosuly. (wayyy too many draws)
But this was done with Manchester United, first season, no signings. Just shows the defensive potensial.
The goals i conceeded was three penalties (kinda weird), one giant, giant mistake by De Gea and the last one came from a long throw on Brittania.