I would like to upgrade for our upcoming trip to Rome cashing in points. However, I am not an elite. If I place myself on the wait list, will my chances be greater if I purchase an Y ticket vs. the lowest available fare ticket? Will the elite CO clients be complimentary upgrade 1st before anyone who is using points?

Another, thing to add is that I only need a one-way ticket to Rome as I will be embarking on a TA cruise. Should I spend the extra money on a one way ticket or book a round trip with a high probability canceling the return leg?