I think most of Dominican men live to the standard "Variety is the spice of life", although many don't like black women, morenitas, etc. There's a bit of racism in that matter in the DR.
I know your concern is about the weight of the girl. It's true Dominican guys in general like some meat, but I think it's just one of the many variants that the sexual fantasizing takes. For instance, in Arabs countries "fat" women are very appreciated, because they are women who can fill the bed. Women that are a bit chubby tend to be more affectionate and have very sweet voices. Because many of them have been mistreated and misvalued by society when they're finally in a relationship they're very devotioned and they really make the man feel like a king. Sometimes the component of not having a caring father adds up to the feelings of these women and KABOOM!, you have a woman that really wants to love someone and wants the relationship to work.
Dominican men really like curviness and that doesn't depend on how thin or fat you are -well, if you're too thin maybe one cannot notice that, so a few pounds can make you look better-. About the sexual fantasizing thing: sometimes men think "that flaca (thing woman) has to be a great sexual partner" and they also think "that chubby girl must be great in bed". So it's like they (we) like both things, but we're concerned on how we're looked by society and for that reason end up selecting thinner women.
According to a survey carried out for Dove (the brand of soap produced by Unilever) by the London School of Economics and Harvard University, only two percent of women describe themselves as beautiful. The study revealed that in Brazil, 6 percent of women consider themselves to be beautiful, the double of Argentina, the Netherlands and the U.S. I think it's interesting that the Garotinhas have the highest proportion of women that consider themselves to be beautiful. It has a lot to do with how developed the soap operas industries is in Brazil, and also that brazilians celebrate brazilian beauty.
I wonder what the outcome of that survey would be if it were carried out in the Dominican Republic.
You can see it detailed here:
http://www.dove.com/real_beauty/news.asp?id=566