I have to laugh... obviously you never went to some of my Spanish congregations! Lol... the question is a Spanish congregation WHERE?
I started and spent all my JW life in Spanish congregations in many different countries and of many different social and economical levels. Many in Latin America (Venezuela, Honduras, Guatemala, Mexico), several in NYC and a couple here in Germany. And in my opinion, it is not necessarily the attractiveness but more the ability to present themselves in an attractive way.
But I must say that there were a complete range, going from amazingly beautiful to ugly as !"$!.
In fact, when new galaadites were assigned to our territory and they happened to be females and young, we found them attractive. I guess we felt attracted to the fact that they were different which, probably is what happens for Americans visiting Spanish congregations in the US.
Just my 2 cents!
Vivalavida