Thanks Ken,

I won't add the Dawn liquid directly into the one gallon of windshield washer so I can add whatever amount I want. I have lot's of empty spray bottles so here is what I will do : I will add 5ml in one, 10ml in the other, 15, 20 and will do some trial to find which one do the best job of cleaning whitout creating a soapyness and get messy more than it clean. My guess is it need only a small quantity.

Hope that we will get good weather ( not looking good so far here ) so I can fly a lot this week-end and try my new cleaning stuff

Séb