I feel your pain Hongkong Karnak is very empty as well second only to your server I believe. What we did on our server is just make 1 LS that functions as way to communicate between all the NA Linkshells.

It works out well when someone from LS A wants to get an Ifrit party they ask their shell then jump into the gathering shell and ask. We are able to get alot of things done that way. Shouting is tough because alot of people are bouncing city to city doing local, or gathering.

It may or may not work in your case but we run events almost daily now. And it has brought alot of people together.