I learned a little trick that might work well with that technique. from "American Restorations" of all places. Once you've sunken the soft grain, dilute some black paint with paint thinner. Wipe it on and set it soak in. Once dry, sand the surface, leaving the black in the soft grain. Then stain as normal. It really promotes that "antique" look. Similar process to some of the staining methods folks use on longrifles.