Regarding the CS, it's slightly different for me. I would have said yes to the 38mm... if the dial wasn't black. For this specific model, it has an impact on your size perception. Black dial tends to give you an impression of a smaller size.
So, here, it's really a question of feeling. I already tried the CS in both 38mm and 40mm and I prefer the 38mm version... but the dial wasn't black.
So, I think the 40mm model could be the right decision but it's really my own perception. If you could try them you would have your answer for sure but I can understand that's not so easy :-/
Best wishes
Alkiro