Hi Scott,

I prefer to publish the superserver-port and call it from the webgateway via localhost. So when doing docker run you have to add "-p..." like

docker run -p 1972:1972 .......

which lets you connect to the superserver port via the same port on your host. When using docker compose just add 

    ports: 
      - 1972:1972

in the same ident as the "image" directive which does the same as docker run -p....

In the webgateway add a server configuration with "localhost" an port 1972. Btw.
You could use a different port on your host if 1972 is in use. Therefore you have to change the port after the colon. i.E. -p 1972:51972 to use 51972 on your host.

Hope this might help.