Really depends on the booth and time of day..
The booths open at 10:30. Most of them are not very busy from about 10:30 to 2 or 3. France, Germany and Canada seemed to always be the busiest without fail. You can kinda gauge which booths are going to be the most popular by how many registers are set up and what kind of line management there is.
If there is a pretty decent line I waited 15-25 minutes depending. Most of the day I was right up to a 10 minute wait at most. Obviously you are going at a busier time, so milage may vary.