Q: What does it look like when empty? Could you put up a photo?
A: If you watch the video for the Inside Out Champagne Glasses, there is a shot of an empty glass at the beginning.

Q: 1. How smooth is the glass, i.e. how many bubble nucleation sites are there on the glass? 2. Is the space full of air, or is it an inert gas?
A: 1. The glass is smooth, with the exception of a tiny "bubble" on the bottom. This is where the glass is closed. The two pieces are mouth-blown separately and then melted together while still piping hot. A hole is made on the bottom so that a vacuum isn't created between the two pieces because once the glass cooled, the vacuum would cause the glass to break. After cooling, the hole is re-closed so water/dirt can't get inside. 2. The space contains air that is captured during the production process.