I hope this is relevant.
I guess a rope decision would depend on what constitutes "alpine routes".
A couloir climb with a glacier descent?
A little simulclimbing?
A 30 to 50m 8mm or 9mm cord should be plenty.
For rock routes it seems 60m has become the standard, so beware of coming short on raps with a 50m. When rapping is anticipated, I climb with a 60 m 9.4 lead and 65m of 7.5 mil static that I found in AK. I wish I had the $$ so I could get 70 or so meters of 6mm. If your backup/tagline is static (like 6mm cord)get it a few feet longer than your lead bc/of rope stretch, and you can always chop chunks off to beef up anchors.
