the pocket in the roof is an old drilled peg hole. it takes one finger up to about 1.5 joint, and another finger stacked on top of it about half way. yes the crux is going for the lip - may advice is bring your left foot up into a heel toe in the back of the roof, to the right of your left hand. its tricky to get it in, but then you get your weight onto the heel-toe, pull up to get your chest into the roof and palm out with the left hand till you can reach the lip pocket. better than using the left foot heel hook where your hand is (where the peg is). brilliant problem.