Engage with your present audience, not the one you have prepared for. Look for reactions to your ideas and respond to their signals. If the light bulbs are not going on find another way to say it. Monitor their reactions; it's the only way you'll know how you're doing and what you should do next. If you don't interact you might as well send a video recording of your presentation. It's why you came.
Give an expressive presentation and an enthusiastic presentation and your audience will respond, which is what you want. At the very bottom line disagreement is preferable to being ignored. Use your excitement, pace yourself to give an exciting presentation, use something you know you feel strongly about to build up to an important point or as a springboard to another idea.