I think you have misunderstood the Diaspora concept a bit. It is completely decentralised which mean that there is many people running servers all over the world, (even though most of them is located in Europe due to better data-protection laws). All these servers are able to communicate with each other so choosing one you choose them all.

Joindispora was one of the first pods and is one of the largest. They stopped new signups to limit the workload on their server and to make people spread among the other pods (which is what Diaspora call sepereate servers.) Having all people on one server is a bit beside the point anyway.

You can sign up a lot of places. Here are some suggestions.

Poddery.com - A nice pod run by some very idealistic Indians. The server is located in France though, as Indian laws are a bit dodgy.

Datataffel.dk - Danish pod with a nice admin called Mikkel.

You can see more here: https://podupti.me/

I hope that you try it out. If you do you can add my two public profiles: jakob@pod.orkz.net & katharsisdrill@datataffel.dk - Just write me in the messaging system if there is something you want to know.