It's actually relatively simple. I just needed to get the resultset, first:
$resultset = $client->select($query);
And then get the full Data from the $resultset:
$resultData = $resultset->getData();
Then I was able to do something like this to parse them out:
if ($facet_ranges = $resultData['facet_counts']['facet_ranges']) {
foreach ($facet_fields as $facet_name => $facet) {
// Do stuff here
}
}
..The best part is that this can work for any otherwise non-supported element of the Solr response, like Clustering and stuff.