Walnut cradle.

Have some cracks/end splits that I would like to use a filler on. I'm having a time trying to match the color of the putty to the different color of the wood[heart/sap, etc. I'll put a coat on first[Deft Clear Lacquer Gloss]. Have been trying to use FAMOWOOD, but the colors aren't available to match good. Was recommended to use a color stick/pencil after first coat. Anybody familiar with what type stain can be mixed with the FAMOWOOD to darken it for matching different colors of the grain.