It depends on your comfort with exposure, really. The crux would go just fine with a 30-40m rope, and the rest is 3rd to low 5th. If you're doing the full ridge, a 60m rope might be nice for the fixed line traverse, as the line is questionable, and you have to climb a ways above the fixed line in sugar snow before reaching a good spot to belay the second.
"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)