I originally fitted a control valve to my poles and found that I got fed up of using a second hand to reach over and turn the water on and off. It also wasted a lot of water whilst I was reaching over to turn it on and off.
So in response to other posts about using the Numatic George trigger I fitted them to my two poles and they worked real well.
On my first day with them, 125 ltrs lasted from 8.45am to 3.30pm with no break. I was doing upstairs only wfp, 2up & 2down houses back & front for most of the time and was amazed how far the water went. This was critical for me as I too am on a meter and can't afford to waste a drop.