RSS Feed with Query from conditional custom feed

I have several posts that have custom field’s attached to them that I don’t want to show up in the RSS feed.

This is my attempt, but somethings not right…

function ke_rss_exclude_filter($query) {
  if ( !$query->is_admin && $query->is_feed) {
  $meta_group = array (
     'relation' => 'OR',
                    array(
			'key' => 'exclude1',
			'value' => 'crit1',
			'compare' => 'NOT IN'
                         ),
                    array(
			'key' => 'exclude2',
			'value' => 'crit2',
			'compare' => 'NOT IN'
                         ),
			);
    $query->set( 'meta_query', $meta_group  );
  }
  return $query;
}

add_filter( 'pre_get_posts', 'ke_rss_exclude_filter' );

I think I’m getting confused on several similar functions and functionality, and just need some pointers on pulling it all together.

All help / comments appreciated.