I thought i’d throw in my 2 cents on finishing walnut. First i dye the wood with Yellow Ultra Penetrating Dye from Bhelen or Mohawk than i put on a coat of amber shellac [mixture of 2 lb cut amber and Zinsser’s Clear & denatured alcohol]. then i wet sand everything with 320 g sandpaper. Then i put on 3-4 coats of lacquer. I usually spray on the lacquer using Bhelen or Mohawk’s lacquer that comings in aeorsal cans. I like the lacquer that has a high solids content. it’s called Finisher’s Choice. The yellow dye really makes the grain pop and cuts the darkness of the walnut.  I’ve tried using other dyes like red, green & orange but i like the yellow.