Many women who are almost all-gray color their hair blonde or get blonde highlights. Blonde blends in better with the all-gray growth as the crown and roots grow in. Blythe Danner, who is going gray, has a gorgeous hair color here.
Most colorists use permanent hair color to color gray hair. It offers much better coverage than semi-permanent dyes. If you are dye-ing your own hair, consider using a paintbrush to apply hair color. According to Scrivo, "Applying color with the tip of the nozzle does not have the same force or friction." Scrivo uses a brush to jab the color into the roots of hair.