hmm very interesting he makes a lot of sense and i already use a spray bottle although it broke last month.
I used the steam clean forklifts years ago in preperation for painting and used a pump spray bottle to spray on degreaser for a bit of pre soaking and he's quite right because on hot days i started using it for car as it was drying before i got a panel done. There is method behind why i started doing this and it is because the engineers used to pinch every F$£$£$£ bucket on the yard so started spray and washing.
We had a nice big karcher diesel steam cleaner which heated to around 130 degrees i think (which i miss dearly), so i used to and still do pressure wash the car throughly and spary concentrated soap solution as i went around the car cleaning the mit after each section like in the video with a hose. As the car dried very quickly i used the pressure washer to soak the car which i found very labourious as your picking up the lance every two minutes
I must admit though my methods change depending where i'm washing the car. At my dads he only ever has one clean bucket so keeping the mit and water clean is essential lots of pressure washer use and bucket refills, at home i have to clean on the street no water supply near by so two bucket method lots of buckets of water, and at work i'm lucky as i have a canopy to work under, pressure washer, tap on wall so all round cleaning is much much easier i dont tend to use a bucket at all and use hose to clean the mits (one for top of car, one for bottom and one for a second wash).
At work i feel like i have acheived the best least painful clean to my self and the paint work by using lots of clean water to rinse and wash as i go around.