The place where to dispute the confrontations is free, as long as it is agreed by the two couples that face each other. Logically, the playing area must be respected as much as possible, but there is no limitation on whether it is played in a club or in a private urbanization. 

Yes. You can participate in more than one category. It is designed so that, for example, a boy can participate in the male category and in turn in the mixed category, and the same in the case of a girl. In this case the price of the ranking is the same regardless of whether you register in 1 or 2 categories. If this is your case, you must register twice on this page, once per category and clearly state in observations that you are going to participate in more than one category.

Indeed, it is a single ranking that encompasses all categories. The Swiss system is used, which always tries to match matches in which the pairs that face each other have the same points. In this way it can happen that there is a female partner who has 4 points and has to face a male partner with 4 points. It is understood that both couples having the same points have a similar level and the gender of the participants is not considered.