It looks like my initial poster-signing schedule was erroneous. It turns out the convention center opens at 2pm tomorrow (Friday), which, it turns out, is after the planned 11am signing. So it looks like I'll just be doing it on Saturday from 11am to noon.
I'll be at the convention all three days, and the posters will be in boxes behind somebody's table, somewhere. If you see me roaming the floor and you want a poster, we may have to conduct the transaction like a smack deal. I'll send a runner to the stash and have it brought out to you, barring the appearance of 5-0.