B7FF: I have some thin finns in 30 and also some NC's in 27. The NC's are tight as hell, but if that's what you want, then you'll be fine. The last pair I bought, though, I switched to two sizes down instead of three (APC 28 instead of 27) and I'm more comfortable.
What I want to know is, where can I get some dark grey petit standards in size 28? They have the jeans at Tres Bien, but only in 30 and up. They aren't for sale at apc.fr, either. Any tips?