SEO for Spanish niche site

I'm promoting a Spanish language info product. As an info product there are no country restrictions. So, my question is, should I use geo-targeting in GWMT to target the country with the highest search volume for the keywords I'm going after or try to rank in multiple Spanish speaking countries?
When looking at the competition I often see the same websites ranking in several different countries.

Spanish is spoken is a large no. of countries. So, I would not easily geo target it unless you have a target audience.