Use Chrome Headless with Behat

behat.yml

default:
    extensions:
        Behat\MinkExtension:
            base_url: http://localhost:8000
            default_session: selenium2
            selenium2:
                browser: chrome
                wd_host: http://127.0.0.1:4444/wd/hub
                capabilities:
                    chrome:
                        switches:
                            - "--headless"
                            - "--disable-gpu"

    suites:
        default:
            paths:
                - "%paths.base%/features/"
            contexts:
                - Behat\MinkExtension\Context\MinkContext
                - FeatureContext

@jdecool I am trying to change the initial window size:

default:
  extensions:
    Behat\MinkExtension:
      files_path: %paths.base%
      base_url: 'https://sp.dev.cms'
      default_session: selenium2
      selenium2:
        browser: chrome
        wd_host: 'http://localhost:4444/wd/hub'
        capabilities:
          chrome:
            switches:
              - '--headless'
              - '--disable-gpu'
              - '--window-size=2000,1000'
    kolev\MultilingualExtension:
      default_language: de
      translations: translations.yml
  suites:
    default:
      paths:
        - '%paths.base%/features/'
      contexts:
        - FeatureContext

But it looks like --window-size switch is being ignored. Any ideas how to achieve that?