I mounted mine to the lid of the freezer using toggle bolts and some nylon spacers. I have it blowing downward with the controller probe in the air stream directly below it. I'm using a 110 v AC muffin fan:
I run the fan continuously 24/7. I figure it costs about 5 cents a day to operate at its 22 watt rating. The lid mounting keeps the fan completely out of the way and the hollow lid made for easy mounting. This also makes it easy to run the power cord through the collar along with the controller probe.
The fan made a huge difference for me. Huge!