"Guys, both ropes in the same biner is not ok.
ropes have a bazaar tendency to unclip themselves.
1. place pro
2. clip 1 biner to pro
3. clip one open sling to biner (don't use a shorty sport draw)
4. clip 2 biners into sling
5. clip 1 twin rope into each separate biner
this essentially works the same as a single rope system with the added safety to prevent both ropes from unclipping themselves simultaneously.
. . .
alpine climber for 25 years."
I see your point about twisting etc. However
this is a 30 meter rope, fewer placements, less
chance for kinks.
And this is a ultralight web site where we assume
people will use judgement in place of extra gear.
If I was climbing at the difficulty level where twin ropes
in a single biner were causing problems, I would
likely move to a double
rope so I could separate the ropes to
reduce friction. This would likely be lighter than
carrying double the amount of biners and a twin ropes.
Double ropes come in at near 8.5 mm versus twin ropes
at near 8mm.
In other words, if you have to place two biners at each
protection point when using twin ropes, there is no
reason for twin ropes to exist.