I would said that average should be 20% less that what you invite, however if you get a special contract with one hotel or two you can track the number of guest you will have for sure about 3 weeks prior the wedidng, by their reservations, whit ths time you can release some seats with your catering and any other supllier without any penalties. It is important to find a hotel with a good rate your guest will appreciate. When are you getting married? This is also important, cause seasons in the hotel industry change as well flights. www.theweddingmexico.com