Abs, MB is very flat and level during the day.
However at night it develops some alarming gradients. It's not unusual to see intrepid campers struggling sideways and making heavy weather of a short journey to the bushes. Sometimes they link together in a sort of traverse manoever. I'd estimate around a 1 in 4.
By Wednesday it'll be around three quarter full, especially the North Face, so I think it'll be a case of pitching where you can. The only places worth rushing for are near the standpipes, but they'll be gone by Monday.
You'll be alright on the night.
H