Well, I was headed into the big city (not Tokyo or Osaka) and had my heart set on one in particular, with another two backups, and all of them were completely booked ('she's very popular'). Looking at their 'items', it is clear that different girls have different strokes. I assume that the women with the standard set are not as devoted as the ones with a large complement of items. I had called a week earlier, and they asked if it was my first time, which I said yes, so I believe that they may let regulars book in advance. Since the trip was just for this, I'll have a chance to go to the big city next month for a longer period of time, and will try at that time.