In reply to Voltemands:
I think the guide says that 15 is standard on most medium length (ie. 30m) routes. More than that and it tends to say in the guide. I think on long (ie. 40m+) pitches you could easily be looking at 20 - 22 draws per pitch or more. I have taken something like 60 draws in the past between me and my girlfriend, especially useful if you intend to work anything over a couple of days or more, although some have suggested this may be OTT.
I have done 40m pitches on Kaly at 6b+ and 6c and many are utterly brilliant, the 80m rope will be a good investment. How much you need one depends on how much you like long routes!
A top tip is that on kaly the long routes are generally easier for the grade than short ones, provided you have the stamina to keep pulling.