Youtube parameters within WordPress embed code?

It doesn’t look like load policies are configurable with WP’s auto-embed.

But see the docs on how to use WP’s embedding: http://codex.wordpress.org/Embeds

And see the Developer Resources and API at WP: http://developer.wordpress.com/docs/oembed-provider-api/

WP’s auto-embedding uses oEmbed, and the specs and API are here: http://oembed.com/