I have been working and struggling with colored pencils for a few years now and I need to have someone who is advanced or an expert in colored pencils to answer these questions.

1. I have been using turpenoid and prismacolor pencils on stonehenge paper recently in order to get my drawings to look like paintings. When doing areas very light in value, how do I create very subtle details and slight changes in value? (such as a face in strong light with subtle changes in tone)These things are easy to control in graphite since graphite is powdery and it travels beautifully on paper, plus it can be modified with a kneaded eraser so you can create the moste subtle changes in value and detail. Now with colored pencils, if I put down a rather thick layer of light peach, go over it with turpenoid and then put a color darker in value with very light pressure, it doesnt go down on the paper that easily since colored pencils are wax based and the layer of light peach is already waxy. So drawing on top of areas that are light in value is very hard for me and I cant seem to do it.
Plus there is this ugly "speckled, blotchy" effect when I again go over the area with turpenoid. No matter how may times I relayer colors, add turpenoid, etc, I cant get my colored pencils to look beautiful and smooth like my graphite drawings. Any ideas as to what I need to do? I keep my pencils sharp, brush away any crumbs, and I do all the stuff the other colored pencil pros do but nothing works for me. Please help.

2.Is there a way to work subractively in colored pencils? The kneaded eraser doesnt lift wax up that well.