Specifying D3 Force Graph parameters via json

Question

I am trying to create a more reusable version of force directed network in d3.js. My thought was to be able to use the json file containing the data to also specify network properties.

{
  "nodes":[
    {"name":"Myriel","group":1},
    {"name":"Napoleon","group":1},
    {"name":"Mlle.Baptistine","group":1},
    //etc.....
    {"name":"Child2","group":10},
    {"name":"Brujon","group":4},
    {"name":"Mme.Hucheloup","group":8}
  ],
  "links":[
    {"source":1,"target":0,"value":1},
    {"source":2,"target":0,"value":8},
    {"source":3,"target":0,"value":10},
    //etc....
    {"source":76,"target":62,"value":1},
    {"source":76,"target":48,"value":1},
    {"source":76,"target":58,"value":1}
  ],
  "graph":{"charge":-220,"linkDistance":50}
}

To do this I moved the call to the d3.layout.force() into the json call see this jsfiddle.

I then specify the graph behaviour as

var force = d3.layout.force()
.charge(graph.graph.charge)
.linkDistance(graph.graph.linkDistance)
.size([width, height]);

My question is if this is the right way to do this. The only drawback I can see at the moment is that it takes a bit longer to initialise the graph. Is there a better way?