In reply to climbtim:
> Sorry to be more specific Alpine ascent of a 6400mtr peak graded Difficile
Oh okay... so you are actually climbing. Not just extreme hillwalking.
In that case I'd avoid a down jacket all together. I'd take a sythethic hooded belay jacket, as they are much more robust and would be far better to climb in when you actually need to.
I went the Karakorum last summer to attempt a 6600m rock ridge in alpine style.
We wore a similar set up to what I'd normally wear in the Alps.
Legs:
wicking pants
softshell trousers
paclite over trouers
Torso:
thermal top
fleece hoody
hooded windshirt
sythethic pullover
In the bag we also had:
A proper Goretex jacket with a good hood, rather than a light one I'd take in the alps.
Very thin thermal leggings. (They weigh next to nothing and add a lot of warmth.)
A belay jacket with a big hood. We took the Mountain Equipment Fitzroy, which we found to be suitable for our needs and a very well designed piece of gear.
Also I'd take plastic boots with a removable inner rather than fancy zip up boots. In my, bitter, experience the later aren't very waterproof and near impossible to dry once soaked.
HTH