Drawing on Wood

I have been working out how to build up drawings on primed wood and then keep then there. I am quite hopeful that I may get this to work.

Below is the first stage of the next drawing that I have underway.  I have prepared  the first layer of the drawing by just drawing on the primed wood with pencil. Next I will fix it with matt spray varnish, add some white acrylic, a layer of thin shelac and then more drawing.