Your basically spot on the only step your missing is a seal coat .
I thought you might like my attempt at a synopsis of a ref. I have on a Panzer grey Mark IV. Sorry if it's still a bit long in the tooth. I didn't want to leave out too much detail.
* The filter step of the hairspray technique involves painting the model in its base camouflage colors
and markings have been applied and sealed using clear acrylic
*A couple of moderately heavy layers of hairspray are applied over the whole model
*A thin , patchy coat of ( well thinned) acrylic white paint is sprayed over the base grey color. ( the author states it can be left overnight but he likes to get straight to work on it. )
*Tools and materials used for the process: warm cup of water, wide flat brush for painting water onto
surface. Medium sized brush and finer brush that are cut down to resemble stubs ( used to remove
paint). A pin needle and sharp toothpick ( for small scratches and scraps)
*In order to start the the wearing process of white paint, apply water to small sections at a time.
*After a couple of minutes the water will soften the hairspray underneath the paint. Use a small cut
down brush to remove small areas of white.
*For small scratches and chips apply some more water and drag the needle lightly across the surface.
Avoid scratching the base coat in the process.
*Softer contrasts between the grey and white are achieved by lightly dry brushing grey with a flat brush.
Achieves a subtle worn down appearance
*A dilute wash of dark earth and small amount of burnt umber oil is applied liberally onto model. This
tones down harshness of the white .
* Shadows around the smaller details can be strengthen by applying a dark pin wash. Wetting the area around the details with thinners first will help this.
*A dilute black wash is dotted around detail - the previous application of thinners help draw the wash
around it.
*Acrylic white is used to add fine highlights along edges of the scratches and paint chips.
*A dirty brown wash of light earth is applied on the horizontal surfaces for depth and grime.
*Use a black pencil to darken edges where white paint has worn away.
*To represent streaks and rust, use a small brush to add dots of burnt umber oil paint to a few areas
*Using a clean brush dipped in thinner drag down the oil paint to represent subtle rust streaks. Avoid
over doing.
The End 