That sounds reasonable. My husband is traveling to Sicily this summer and will have the Roll-avanti plus the 21inch roll-aboard. He will probably have the avanti as his carry on and just check the 21in: however, if he is allowed 2 carryons, he will have both with him.
He may not even be using Luthansa: however, they seem to be the most strick. I figure if he can pass their regulations, he shouldn't have too much trouble with any of them.
I think I am more worried about his trip than he is. :D
As for me, I will traveling to California for a few days and have the RS convertible. I do not anticipate any troubles whatsoever. :D