It takes some doing but works, I slide the radiator hose back enough to start to drain and then when the pan is full, I slide it back. The process is repeated several times. I can get about 5 1/2 liters or a gallon and a half a pan. But you can always jack the car up and get a 12 liter plastic dishpan or oil catch bucket and then use the foil for when you lower the car to get the last of the coolant.
I like the excitement of the foil approach though. At my age the thrills come easily.