So, I presented Gradient to about 8 people + 2 friends of mine (thanks for the moral support, Gael and Torrey!), which was interesting.
For a couple of minutes we had no video cable, so I chalked up a bit of stuff, like the URL for the presentation, and waved the laptop* under people's noses so they could read SVG and stuff.
It seemed to go OK. I didn't stutter, freeze up, stumble over my words or anything like that. However I'm not convinced I explained Gradient as well as I could have done. Gael was a great help in showing me how to explain my ideas properly, but I rambled a bit, and the demo's could have been better.
Nevertheless, it was a great opportunity, and it was good to meet Ralph and Heiner (author of Lluna) in person.
* generously provided to me by the company I work for.