US Airways Dividend Miles (Pre-FlightFund Merger) - Space Available vs Space Positive?

So I'm getting ready to make the eurotour 04'. :)

I've been out of the game for a while now doing mostly domestic runs but it's time to refresh on the Italian. And I'm jonesing for some prosciutto y mozarella di buffala. Siiiigh...

ANYways...

I'll be flying Y class tickets. I used to understand the transatlantic upgrade game, but like I said, it's been a while and I'm rusty and who knows what kind of changes have happened.

Can anyone shed light on the difference between the Space Positive and Space Available upgrades? Further, which would be better for someone on a full Y ticket?

Does one trump the other or are they basically the same? I'm a Silver (downgraded from Gold due to lack of the transcons, more's the pity), soooo will that affect my ability with either?

Thanks in advance for any light you can shed on this.

Regards,
-Bouncer-

If, as you say, you have a full fare Y (fare basis Y and B), you will want to use a space positive certificate.

You can only use these on the Y and B fares but the upgrade is confirmable immediately (assuming availability which usually is not a problem). If you use a space available voucher you will be the lowest of all priority for the upgrade (assuming that once everybody else has cleared the list that there is still space available).

Have a fantastic trip!