Maybe I'm wrong but haven't heard of too much flats fishing in the DR. Never been but I think it's similar and close to PR where it's void as well with the exception of Vieques and Culebra. DR and PR are known more for their offshore gig.
There's a Caribean Forum on a famous fly fishing site. I sent you a PM with info.
There's a Caribean Forum on a famous fly fishing site. I sent you a PM with info.