You can do whatever you want with the base vmf. Anything. Valve probably won't like it if you bulldoze their layout though. The more you deviate from the base layout, the higher of a risk you run. When we said layout changes would be disqualified, we meant if you submit 2fort to the contest. Major changes. If your map's layout doesn't resemble the base vmf's layout, you will be disqualified. We will not be nitpicking wall heights, 32 unit changes in doorway widths, small things that have little relevence to the overall layout and flow of the map. Read: unless you're adding or removing paths, or significantly altering where they go, your changes are FINE. Furthermore, posting "you changed the layout too much" in WIP threads will not be tolerated. It is not your decision to make (it's Valve's), and contributes nothing to the author. Thank you.