I use a second coil of copper in a bucket of ice water. With a counter flow wort chiller.
I'm going to give this a shot with my immersion chiller. I was using the hose to get it down close to 100F or so, then using Ice water and a pump to get it down to pitching temps. I think it will go faster if I just prechill the hose water with a second immersion chiller in ice water