I finally converted my 50' 3/8 into a 25' counterflow using garden hose and sweated fittings as shown in the DIY section here on HBT. Absolutely this is faster than what I was getting before, probably less wasted water, but I'm missing the ability to cool wort to 190 and then let my flame out hops ride 20-30min on a slow ambient chill down to 170 or so before turning the water back on and chilling the rest of the way.
Maybe I need to recirculate the counterflow back to the kettle to duplicate what I was able to do with my immersion chiller, but I don't own a pump yet.