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.
"So I was sitting in my cubicle today, and I realized, ever since I started working, every single day of my life has been worse than the day before it. So that means that every single day that you see me, that's on the worst day of my life."
--Peter Gibbons (Office Space)