do you add any prismacolors in the end? or maybe guache? Something to puch out the whites or dig deep on the dark end?
When you get your hands on some letraset. Try adding your black or dark grey in step 12 on the backside of the paper. This way it won't intrude, and you can continue to add color on the top side without the black beating it up.
I like your style. Do you have any rods?
oh!! you try frisket?