Start on the lowest deep slot, after two short moves to another slot rail, make a big span to a tiny intermediary crimp, and then set up feet, and explode to the sloper at the top. This is one of the most obvious and pretty lines at Conway. If you start at the upper slot, it brings down the grade to V5. 

The far left side of the Marble boulder, its easily identifiable from the slots running up the face. Start at the lowest slot.