Expanding Octave for the Newbie

Hello Theremin World!  I recently built a vacuum tube theremin, but had my eyes on an Etherwave.  I found one used locally on Craigslist at a reasonable price. I built and installed Dewster's bass extender mod and am very happy with it.  I am using a slightly modified version of Carolina Eyck's fingering method and after 2 months or so, I can play several rather slow songs with relatively good pitch.  Now it's time for me to expand my 1+ octave range.  Does anyone have suggestions on musical exercises to do and/or videos to watch to get my arm moving to increase range?  For example, when I move my arm to a new octave, which position should I use, ie 1-8, or does it depend on whether the song is moving up or down in the scale?  I have figured out that I should start a song with a particular fingering, as to try to get all the notes in, without having to move my arm too much.  Is this a good idea?  Any suggestions would be welcome.