When you use fan jets you try convincing the customer that your not using a jet washer lol because that`s how it sounds and looks on the glass and i reckon you will get a lot more people moaning about the water or the amount your using and leaving lying around.The rinse is all in the brush and how it will allow water to flow through it,if you use a Vikan brush you`ll find the water will get trapped and even with a good flow of water you`ll still leave bits behind on the glass,where`s with an SL brush you can rinse on with pencils confident that the result will be top notch.