The problem isn't so much the brushes nowadays... it's the damn blower at the end they use to dry. It's so powerful that it'll push water through the seals and mess with the top.
I TRIED a PetroCanada GlideWash with soft cloth for the vert, got scared shitless when those jet engine powered turbine driers started rattling the windows at the end. I 'jetted' out of there, needless to say! I didn't choose the 'touchless' for that very reason... super high powered jets... no good!
http://retail.petro-canada.ca/en/formycar/2599.aspx