While the barrel cased Carreras are only slightly thicker than the other automatic Carreras (a matter of a couple of mm), the perceived thickness is much more. This is probably because about 2mm of the 1153 case is the rounded perspex, whereas the 110.573 is pretty much steel all the way up (the mineral glass is barely proud of the case at all).

I took a rough and ready comparison shot (which turned out rougher than I'd hoped, my camera does not like photographing anything close up, even in macro mode) of a 110.573 and an 1153:

Hopefully, it's still enough to show that the barrel carries its centre of gravity much higher than the 1153, making it feel very different on the wrist. I find the 1153 and derivatives to be immediately comfortable, whereas a 110.573 takes some getting used to and can feel top heavy. In the end, you do get used to it but, if I had to choose one for comfort, I would take the 1153 every time.

Mark