I guess the main reason for using web sockets is to allow async?

I've implemented similar designs for several projects; but I've been piggybacking updates on regular http requests, clicking a button etc.

I just put the page state in a LIFO with a big enough max limit on the server, clearing out anything older.

You do have the limitation of being stuck with the sever that answered the original request, but erlang should be a good platform to fix that.