Language question about how to call (name) the girl you're approaching

[psd]

OP: ちゃん is way too familiar for someone you've just met, IMHO, nampa or not... I get a similar feeling when some older women use "darlin'" on me when we've just met (often restaurant or hospital staff)

I was going to make that point but a bit stronger. You should probably not use Chan with any adult woman. San is always appropriate even if feels too polite to a Westerner.

Chan seems to attach to some women in a way that's hard to understand. In an office there might be one or two women that get called chan because it suits them (not necessarily because they are girly) and there may even be men that are called chan. I knew one mature woman who everyone called Itoh-chan because she hated her given name, another who was -kun because she was a tomboy as a kid and it stuck. And some nickames, Asuka -> Atchan. Listen to what others call her and copy it.

In my decades in Japan, an older man, only two women have called me chan but it seemed normal, anyone else would have got a mouthful of abuse in response.

 

[CharlieSimms]

You should probably not use Chan with any adult woman.

I think it depends on your relative age and relationship to the said adult woman. In my personal life especially in the night world, 90% of times will always use first name with chan or first name with nothing following (呼び捨て). I am addressed pretty much always in the same way. There are exceptions but rare. Obviously very different in the professional world.