start out slowly . do it properly and speed will come. average semi used to take us about 20 minutes when first started out, but never got a complaint . rinsed twice used too much water etc. now use half as much water and in half the time. never had a complaint about spotting and now do over 100 houses of all types of windows . practice and patience .
how come some windows bead up and look rubbish and otheres sheet straight off? Its really a steep learning curve. Here's an explanation about the two types of glass:www.cleanitup.co.uk/smf/index.php?topic=57783.0Here's a short movie showing the differences between the behaviour of water on two types of glass: www.cleanitup.co.uk/smf/index.php?topic=58362.0