Not so Radical Voice

I'm progessing on my look at the voice and tone we would like for the exhibition. We want to have a friendly, open conversation with our visitors. We would like for them to understand that we're a bunch of Museum folks who have worked very hard to present an interesting experience, but that we've made choices, and we have our own perspectives, too.
So far, we've defined some objectives for our voice and tone:

• Be respectful of choices, opinions and perspectives. To do so, we must be open about our own choices and use language that shows this.
• To show that outcomes -history as it is traditionally presented and understood - are not inevitable. Dialogue and debate are central to the stories and processes covered in the exhibition. Our text must reflect and continue this dialogue.
• Peel away the history. Encourage visitors to consider their own choices and reactions if they were confronted with the events we present.

We think we know what the characteristics are, too. Active, concise, open, inclusive and conversational. We even want to have peaceful language, that is we want to avoid using violent metaphors. This last bit has been interesting for me, as I've become aware of how prevalent they are in what I usually write or say. ("We need a bullet-proof defence!" "I've been fighting my way through all this reading!")
Now for the challenge. This is a complex exhibition, with some sticky issues and events. The pressure to be absolutely accurate and in line with the museum's mandate is quite strong. You could say some have put their guards up, but that would be a violent metaphor, and I am trying to avoid those! We presented some samples and they were met with cautious, conditional support. The conditions are that we have to prove that people will read and enjoy this text, and that we will not alienate anyone. So I've got a reading list as long as my arm, some ideas for readability tests and a timeline of September. I've found good resources for using questions, good current discussions about multiple voices, but not too much about conversational tones. I will keep looking!
Today, I read:

Write and Design with the Family in Mind, by Judy Rand in Connecting Kids to History with Museum Exhibitions, D. Lynn McRainey and John Russick, Eds., Left Coast Press, 2010