I have huge lungs, so this is not really a problem for me. Still, I'm intrigued: is there really that much to be gained from getting your CLs sewn up?

Won't small CLs using a larger portion of their capacity stand out proud from the body more? Properly clippped off at the bottom, they shouldn't really be flapping around.

And I feel some comfort in knowing that I can use the CLs for added buoyancy in a pinch.

Since water gets directed to the CLs, to help protect us against caustic cocktails in the Meg, I find some small comfort in knowing that there's plenty of space for that water to go.

Finally, for an average-sized male (which I'm not) tidal volume is 0.5 litres, against a total lung capacity of 6.0 litres and forced vital capacity of 4.8 litres. That must mean that big breaths in an emergency are far larger than typical breaths. Take a look at this and tell me what you think:
Lung volumes - Wikipedia, the free encyclopedia

As ever, I have no axe to grind: I merely humbly seek knowledge