I recently upgraded our cash economy boarding with Avios. Like others have said, they would not tell me if there was any Avios upgrade availability beforehand, so I took the risk and transferred Chase miles to Aer Lingus Avios. Once I did and made the upgrade request for my wife and I, it was approved within 4 hours. I did this 3 weeks before the flight and there were 12 open business class seats. Expert Flyer showed no upgrade seats available, so I wouldn’t count on that before doing it.