Like I said earlier, it was hard. We found the key being setting the sensitivity of the sensors when we got to the competition. We went to the practice field and watched the lights on the sensors while moving the robot around above the tape (including the nice black tape that is on the field). Once we did that our code that we had working at home seemed to work pretty well, but there was still some adjusting to the straight line and cornering speed for us. We use a meccanum drive also, but don't drive straight with a gyro. Instead we actually corner the robot.
You can see it in action at 2:01 to 2:11 in this video.
http://www.youtube.com/user/Broncobo.../6/e1xuGX7l4j8
Message me if you want more information.