DreamObjects bucket alias and PHP SDK

Setting up a CNAME alias for a DreamObject bucket (private) based on Knowledge Base tutorial and trying to figure out how to combine/access it via the PHP SDK

Using the SDK, I define the HOST as:

define('HOST', 'https://objects-us-east-1.dream.io');

For grabbing private items within bucket and producing temp URLs, use the following code:

$cmd = $client->getCommand('GetObject', [
	'Bucket' => $bucket,
	'Key'    => $key
]);
return $client->createPresignedRequest($cmd, '+1 week')->getUri()."";

This returns a URL along the lines of:
https://bucket.objects-us-east-1.dream.io/key?authtokens

How/where should one change settings within the SDK so it produces alias URLs?

Furthermore, the question has been asked multiple times… are bucket CNAME alias’ http only? Seems like it would be implemented as everything turns https (ie. issues accessing non-secure items from a secure website) or does CNAME alias actually return a secure item?).