Ok, I'm sure this has been discussed at length, but with no search function, and after searching through hundreds of posts, I can't find it. So, I appologize in advance.

Since these are good for day of travel upgrades only, one tip from the AS forum is to call at midnight of day of travel to request. Since I normally fly out early, I'd prefer not to stay up until midnight if there is no chance of an upgrade, I've taken to calling NW the day before to ask if there is any availability, and/or if there is already a waiting list.

I think I understand that upgrades come from the "R" bucket, the same bucket as award tickets and some discounted F tickets. The "R" bucket is not displayed on itn like the "U" bucket is for Alaska, so there doesn't seem to be an easy way to determine availability. Now, if I do a dummy F booking, and find that it books me in an R bucket, then R is available at that time. Similarly, if I try to do an award booking, that would show "R" availability. Are these assumptions correct? Is there any easier way to determine availability?

Thanks for your informed answers!