I'm sure you've done it already... but just to be sure - did you claim a new plot, exit right out of SC (not just to the main menu) then relaunch and go back in to that plot? That's when you should see the larger boundary lines. Good luck with it!
Wow, after reading like 20 pages trying to make this work, you solved my issue! Should clarify on the front page that you need to exit ALL the way out of game, and not just to the menu. Thanks!