I'm chiiiiiiiiiiiiilllllllllllll.
Just don't think its funny to poke fun at people with dyslexia or that just can't spell as good as others.
I'm sure tench won't be offended, but just thought it needed to be said.
Anyhoo....
Back on topic......
If I had to use only WFP on builders clean I'd make sure to get them to sign a scratch disclaimer.
And then use a very high flow rate, with a flocked brush while spraying the brush head every window with a degreaser.
Then rinsing out the brush head every other window in a bucket of pure water. Will be pretty time consuming, but should get ok results.