The maximum length of the entries is 7 min (mine is 6:17), so the screening should be over at around 10:45 or earlier, and frankly nothing stopping you from leaving earlier. We tend not to take the screenings too seriously since most of us just make these films for fun, even though it is a contest. Best guess 3-4 will be good to great, 5-6 will be mediocre, 1-2 will be bad but over quickly, and a 50/50 chance one will suck so much you will wish you were dead (this is when you go and get drinks) .

Adam