More Detailed Country Polygons on D3 (Puerto Rico)

Question

I am following the tutorial of map making and I wanted to have my map zoom in on Puerto Rico (as opposed to the UK) in the tutorial.

To adjust the project parameters though, I had to rely on tinkering with the values as what I would expect didn't come out.

I'm currently using d3.geo.mercator() instead of albers()

var projection = d3.geo.mercator()
  .rotate([66.1, 18.4])
  .scale(10000)
  .translate([width / 2, 6.2*height]);

though I want to do something like the below (which makes the Puerto Rico path appear off screen - can't see anything).

var projection = d3.geo.albers()
  .center([66.1, 18.4)])
  .rotate([0, 0])
  .scale(10000)
  .parallels([15, 25])
  .translate([width / 2, 6.2*height]);