It might help to mention the increasingly unreasonable takedowns coming out of the entertainment industry as indications of why this is unbalanced. (Like, for instance, Universal's recent takedown of a MegaUpload promotional video in which they admitted knowing they had no intellectual property interest whatever.)
Also, it might help to mention costs of compliance for small startups that feature user-created content, as a fraction of total expenditures, if you (or anyone else at the meeting) has credible figures and is in a position to disclose them. (The Reddit "SOPA will shut us down" post is a nice start, but I'm not sure they've posted the numbers to back it up, and you might need those to be really convincing.)
Lastly, there's the DNSSEC argument, which is open-and-shut if the guy is technical enough to understand it. But if not, well... look at some video of the abortive Judiciary markup to see what you're up against.