I've just fitted a Dayco 7PK1605. I had to cut off one rib which I did with a brand new blade in my Stanley knife, stabbing the knife through the rib and dragging the belt through the knife holding the knife stationary. I believe that you could probably go with a 1580 (mm) belt. Cutting off a rib is done "all the time" according to the hose and belt guy.
It took a while and a few wasted belts (finding the right size - vcutting it was a breeze) but in the end I am running all pulleys except the air con (which I'm going to pull off to repair but but wanted to drive the car in the meantime.
It took a while and a few wasted belts (finding the right size - vcutting it was a breeze) but in the end I am running all pulleys except the air con (which I'm going to pull off to repair but but wanted to drive the car in the meantime.