I figured that was what you wanted, I just wanted to be sure.
Also, for convenience, here's a .zip with some base maps. Each one has a box in the center. Anything inside the given blocks is in the 15 X 15 X 15 box. If you build into the ground, you'll need to adjust the ceiling since the bounds have been lowered. Note that the blocks given are NOT within the bounds and need to be removed before submitting. You'll also want to change the comment; that's just to remind you of what I've stated above.
[EDIT: MTC building is over, so I've removed the .zip from my dropbox]