piglet is correct: the left start up the corner in the six start. the four start move up and right, then back left again on the first foot-sized ledge with not much positive hands.
and rg, thanks for the history. it kinda makes sense in that i read something that said the third pitch (roof, from the gt ledge) feels more like a six. based on that, there could be your interpretation or the one i'd always thought, which is that it feels harder than a four after the traverse right (the move up and out). but i've never led that part.
and thanks for finally asking about a route i actually know something about. now...any questions on bunny? or black fly/nice crack climb? c'mon!!!