I have been considering just trying it with the 55 and seeing what happened, but my concern was that I have free checked baggage on United flights, but not on their partner airlines, which most of my flights will be, and knowing my luck i'd be forced to check it on one of those flights. Glad to hear someone else is having success. Out of curiosity, have you gotten away with it on any Lufthasana or Turkish airlines flights?

Pics of your setup certainly wouldn't hurt.

Thanks!