Need presentation advice!

I’m giving a two-hour seminar to a mixed audience of faculty, medical professionals, students and the general public at my graduate school in a couple of months. The title of the presentation is “The Truth About Cholesterol: Separating Fact from Fiction”.

Because of the varied nature of the audience, I will be expected to present a fair amount of data - but to do it in such a way that the layperson with no scientific training could understand.

I’m following the format outlined in Presentation Zen (i.e. minimizing text, simplifying charts & graphs and relying heavily on stock imagery) and that is working well for me. I recently bought Beyond Bullet Points and have been trying to integrate some of Cliff’s story structure ideas, but I’m having a hard time with that.

I have some questions I’m hoping the hive mind can help me with.

1) How can I keep people engaged and interested throughout such a long presentation - and still get through the considerable amount of material I need to present?

2) What is your opinion about the BBP suggestion to use full sentence headlines on every slide? I’m finding that a bit limiting and repetitive visually.

3) Along the same lines, I’m having a hard time organizing my presentation in the rigorous way suggested in BBP, i.e. with everything in groups of three. My mind just doesn’t work that way, and there’s something about the hierarchical structure that feels stale to me. On the other hand, I understand the necessity of structuring the information in a way that is meaningful for the audience. Do you have any suggestions for alternative methods of structuring content?

Thanks for your help. Chris