I'm looking for hair coloring advice. My current hair color is sort of a washed out light ash b

hair tends to go brassy very easily especially the new growth. I would like to go darker, to a chocolate brown but I'm afraid that it will take the color up too much on the ends and then look weird. I think my natural color is light ash brown with a few scattered grays esp. on the crown. I've had past hair color disasters, mostly trying to go lighter and I've had fair results at the salon. Haven't really been able to find a good colorist in this area and my hair always tends toward the golden when I would like it cooler but not too ashy (green) Any advice would be welcome, esp. from pros or those who have colored their hair a lot at home.