We recommend the parallel connection.
The Gemini can produce a variety of line spacings. To illustrate this there are two embossers listed: the regular Gemini and one for using the "small spacing" feature of the Gemini. Notice that you cannot do interpoint when using the small spacing.
In the advanced tab in the configuration setup you can add startup sequences. The command for double high inkprint is: <Esc><Esc>D The command for double strike embossing (slow, but better quality braille) is: <Esc><Esc>Q