Well, some are only 1.63 wide. Although that doesn't necessarily make it less stable, does it? Well, I think he has no interest in that. Maybe he's reading along here?
My partner and I have seen several houses with a clear ceiling height of 2.50m in model homes and were always surprised (well, not anymore after the third time) when we were told this. So I now think that would be acceptable for us, especially if the ratio of the window height to the room height also fits better...