widgets template system using node.js with dust server side templates

I'm trying to create a page with widgets on it using Node.js and Dust as a template engine. I would like the widgets to be standalone as possible with their own css, js and html.

Which of the follow three method is best? which will be the fastest?

Option a: using res.render and rendering only once

pseudo code:
   1) call page route (app.get('/', routes.somePage);
   2) load config file (say /views/somePage.cfg) listing all widgets on somePage.
   3) get widget data if needed (say access another server for the data).
   4) build 1 context object and pass to render
   5) call res.render with context containing page data + all widget's data
   5) somePage template will include partials to build page, including widget partials. 

Option b: using res.write

pseudo code:
  1) call page route (app.get('/', routes.somePage); 
  2) load config file (say /views/somePage.cfg) listing all widgets on somePage.
  3) use app.render() to render widgets + page (running js to get each widget data) 
  4) use res.write() to build a complete page.

Option c: using helpers

pseudo code:
  1) call page route (app.get('/', routes.somePage);
  2) use app.render()
  3) use custom helper to render different widgets. 
     custom helper will actually grab the data and might use app.render inside to build 
     the widget during render time..