Warning: Spoiler! (Click to show)
Thanks for posting this, Hansderhund. You're right, the clothes in this film were fascinating. It looks like my recollection of the San Remo outfit was quite far off but I still think it's incredible in its simple elegance. Could you tell what buttons the SC had? No PS from the looks of it, fairly strange.
Another outfit I've seen that I feel has some relevance to this thread is a black suit that definitely had polished silver buttons, worn by Colin Firth in A Single Man to a dinner at his friend's home. It was typically Tom Ford monochrome style but due to the night setting it looked fantastic. Although too formal for OP's needs, the use of black tie colours in a more casual outfit provided useful inspiration. Brilliant film too.
You were pretty close, I always remembered the blazer in the second pictures. You may have been thinking of those buttons? I can't tell if they're silver or a grey shell.
I haven't seen that movie, so I'll hit imdb right now