what is your job in the Central Bank? I also came from Latin America and I also used to work at the CB of my country, and I know that the type of job you do at research division might not be research. Are you working doing just research?, as a research assistant to senior economist?, or are you working doing conjuncture analysis or forecasting??. I think that there a huge difference depending what type of work you are doing. Specially about what the letters that you get in the CB might say.
Personally I used 5 letters to apply, 3 from professors, and 2 from work (my boss with a phd in UCLA and the boss of my boss with a phd in Stanford, neither of them has published in relevant journals in the last couple of years, just working papers and articles in the CB journal), and I got better results in the universities where I applied just using professors letters (one was my thesis advisor, other one I did RA and Ta with, and the last one a professor I just take 2 classes).
Other thing you need to consider is which else is aplying, for example the year that I applied there were 10 people from my University appliying, and I suppose the same number from the other top school in my country. Normally the programs just select one person per country, specially latin america country, so its important to know who else is appliying. The year I did I knew most of the people applying with me has better grades, so I try to look for programs that fit my profile more specifically, where I could have some advantage.
In conclusion, I think that just working at the CB do not change your profile a lot, so you should include more safetys, and drop some of the top schools you're applying.