Thanks David. That is a good point and something I considered. As I said, it's a group of seven and I expect to be the second fastest alpinst in the group so I'm assuming I'll be going along at a fairly easy pace for myself.
Packing a four layer clothing system seems to be the standard for the Presi Traverse in winter.
Mine is a four layer system so that should be more than enough, even if I'm just standing around for an hour.
I've found that in my baselayer shirt, the mountain hardware fleece, the shell jacket, the baselayer pants and the softshell pants I can even sit on a ski lift in 9ish degree Fahrenheit temps no problem for about 10 minutes. I was also able to climb to 21,000ft in that system which is a very slow and cold climb. Luckily, other than my feet and hands, I'm usually concerned about being too warm.
That's why I was considering swapping the OR Down Jacket and the Fleece Pants for a Big Puffy Down Jacket. It would weigh almost the same (50g heavier) but be more versatile for me I think. I'm not sure about this yet.