In reply to jasen:
It's not too hard to go wrong once you are on the route - the link provided is probably as good as you are going to get. The Piola guide has a topo but whether it's any different I'm not sure.
The lower slabs as far as the first terrace are exposed to stonefall. Once you are on the climbing above this, it's steep enough to be protected and reasonably safe. It's about UK E1 to the Jammed Block (say F6a/6a+). The 90m diedre is pretty solid E3 or F6c.
ALC