Did you ever measure the height of the opening of that overhead bin? I suppose that is the limiting factor, no? I looked at photos. Looks like 8 inches.
You don't say what kind of clothes or what kind of load in general you are taking but the Western Flyer is 7" deep (if not overstuffed). If you don't plan to pack a suit jacket the WF would do.
If you pack really light, you might even be able to use it as a briefcase once you are on site. True onebagging. Nice when one can do it.
Till