If I had to advise anyone starting WFP I would say to them save yourself hundreds of pounds and buy 1x extreme the Natural bristle version 1 x medium mono the black and white ultimate 1 x yellow and white medium ultimate and 1x black flocked. That is all the brushes needed to clean every kind of window out there more or less and I’ve tried dozens all manufacturers,the above brushes are all Gardiner’s. Like I say only my opinion but I’ve tried so many different types and weights but always go back to the above.