Questions with house washing

Hello all, my name is Bob and I am inching closer to getting started in the business of soft washing houses and
roofs, along with cleaning some gutters. I have read up on most things involved in the processes, the forums have been very helpful indeed. Thanks to everyone who has provided that vital info.
Question one is regarding mix to use for the different surfaces out there. Do you use the same on brick as you would on vinyl, stucco, or painted wood? Does the same mix work for aluminum siding? I saw a pic of a freshly washed house on the forums that was mostly brick in the front and vinyl on sides. It looked like all of it had been washed, same mix in that situation?
Secondly, what are most companies doing with screens, should they be removed before washing the house, washed with the house, and is the wash even sprayed on the windows and rinsed during process. Thanks in advance for any help!
I am guessing I will be back with more questions!