Hello, I have a flight coming up from GIG to IAH on April 26 (UA 128) and am thinking about paying 25k miles + $375 for a shot to upgrade to Polaris. Current ticket is a paid Premium Plus seat. I am new to this upgrade situation and was hoping someone could give me some guidance on my odds and if it's worth trying. Below are the available fare classes. Thanks in advance!

• J9
• JN9
• C9
• D0
• Z0
• ZN0
• P0
• IN0
• O9
• ON9
• A9
• R0
• Y9
• YN9
• B9
• M9
• E9
• U9
• H9
• HN9
• Q9
• V9
• W9
• S2
• T0
• L0
• K0
• G0
• N9
• XN0