Bluto,
At the SLC fair, the doors were not closed at 10. We had our hands full getting everyone signed in because so many showed up and we got the same reports from the LAX event this week. If you show up a little after 10, I'm sure you will have no problem getting in for a noon presentation. If we follow our SLC example, there will be more than two presentations (which only last 20 minutes for the introductory part).
Have a good time in PDX.