In reply to Chris Sansum:
> Any reason I should invest in 'twin' ropes rather than 'half' ropes?
TBH, not that I can think of, as most thin half ropes (<8mm) also tend to now meet the CE twin rope standard so there should be no problem with using them that way anyway. Also given that you can buy half ropes as thin as 7.3mm (Beal Gully) there is only a minimal weight saving going for a true twin rope like the Edelrid 6.9mm Flycatcher.
However, as to what is best for the Verdon, I can't really comment, although I am pretty sure the topic has come up before on here.