Determining where voiceover speech is played

All:

I recently obtained a Bose Flex 2 Bluetooth Speaker. Its a great little device, which I will probably write a review for at some point. My question though is about Voiceover speech coming through the speaker. Sometimes I want Voiceover speech to come through the speaker, like when I am doing a demo of an app, but most of the time I want voiceover speech to come out of the phone and just my music to come over the speaker. My question is, how do I switch between these two output sources? When I am connected to the speaker, I went into Settings, Accessibility, Voiceover, Audio. I see controls for both speech channels and sound channels and my Bose Flex is listed, but adjusting these controls doesn't seem to do much. Each time I made a change in this section, I exited Voiceover and restarted it on the phone, thinking this may cause the change to take affect, but no such luck. Also, under Rotor items, I've found an option called audio destination. Its selected, but I can't make it appear when I turn the rotor, so not quite sure what this is for.
Has anyone been able to make Voiceover speech move back and forth between your phone and a Bluetooth speaker with a simple setting?
Any help is much appreciated.
Thank you.
Jim