Not heavy at all! Maybe a little more than a clic clac, but not noticeable IMO.
Hi laurenccharly, I tried to PM you but your inbox is full I think. Anyway, regarding your question with the narrow silver cdc, I have a medium sized one, and my wrist is 16cm. I tried the small size beforehand but it was a little snug, and this was already when my wrist has "swollen up". I just took this mod shot to show you, hope it helps.

Did you try the small size? It might be more comfortable for you.
Let me know what you decide. Goodluck!