How to set display_summary in code?

By default Panopoly Pages doesn't display the Body Summary field. I'm trying to programmatically set display_summary in a Feature, but Panopoly Page doesn't appear as a Features Content Type component.

Solved: I used defaultconfig. Since its project page is vague, here are the explicit steps:

1. Create a new Feature. (This example uses mtms_panopoly_page as the Feature name.)
2. In the Default config section, select the Fields: node-panopoly-page-body component.
3. Export the Feature.
4. In the mtms_panopoly_page.info file, comment out the line starting with features[defaultconfig][]
5. Install the Feature: drush –v –y en mtms_panopoly_page (-v gives you verbose output)

I'm left with a couple of questions: (The editor ignores my unordered list. Switching to an ordered list. Please visualize bullets.)

1. It seems that defaultconfig only commits your changes during a module install. Is that correct?
   1. If so, adding new defaultconfig components to an existing Feature would require uninstalling and reinstalling it.
2. The defaultconfig project page states that you manually have to change function yourfeature_functionname() to function yourfeature_defaultconfig_functionname(), but in my case, the correct function name was already generated. Is that the normal behaviour these days?
3. Defaultconfig generated code to populate every Body setting. I'm only interested in defining a default value for display_summary. If I removed all code dealing with other settings, would the rest of the Body field remain defined (with display_summary getting my default value), or would the Body field be missing every other setting (only display_summary defined)?

Although this deals with a Panopoly field, these questions are more specific to defaultconfig. I will gladly post any answers on the defaultconfig issue queue when this issue is closed.