Ari - I wouldn't worry about the rear of the control room being asymmetrical - it actually helps the low end at the back of the control room. It's the front end that must be symmetrical.
And for Knightfly, the soundlock I'm talking about is the left side soundlock between the studio and the control room. It is intended to be a vocal booth. Actually I'm hoping that it could be also used as a drum booth, but I'm not sure whether the size is adequate.
BTW the soundlock at the bottom right is a great idea, thanks Knightfly.