Perhaps you should emphasize that both buttresses crossed before heading up to the chockstone are both large and continue across the traverse. When I did the route and crossed the first buttress, I saw a second smaller truncated buttress that partially divided two chutes. The farther chute was wide and forked twice, but there was no chockstone! After descending and then crossing a 3rd buttress (2nd continuous one), I was then in the right chute to ascend.
I also took some photos that can help clarify this vague description of where to begin ascending. I'll post the photos soon.