Flying MSP-AMS in the A333, currently reserved window in economy. My hope is that an upgrade to C will be available for purchase at the airport, if not Y+ would be desirable. Is it worth the $100 cost to get seat 12J, or should I rather skip it and hope an opportunity to upgrade to C? Will the price, if it is possible, for an upgrade to C take into account that I am seated in Y+ and not Y? For what it is worth I will travel in late june, it is a night flight, and I am ST E+ with CI.

(If there is any other - or easier - way I can get hold of an upgrade to C, please let me know)