A friend of mine saw this photo on RC.com years ago, after which we spent a fruitless afternoon looking for the route in the Upper Chessmen area. 11a if I remember correctly?
So how many pieces do you have to leave if you don't send? (sorry don't have too much experience with horizontal climbs).
12- it is. Also it is not at the Pumphouse. You have to work your way around to the top of the Andy Cook Wall. It is at the south end. You Can see this roof clearly if you pull into the first pullout on the left after you cross the bridge just after the 7 cataracts pullout, roughly MP 9.1.