Thinking about commissioning one for my fall rotation. One would think it would work for me (silver/grey hair, well tanned complexion), but one rarely if ever sees this color in the wild and the color is seldom discussed here.
Really dark shades of brown are extremely hard to get right, in my experience. They easily take on a manurial/dungy quality, which does no favors to your complexion.
Contemplating a solid with subtle texture (say, a pick & pick). I've seen a charcoal brown at my tailor's in a suit he was doing up for a client. It was more grey than brown. In fact, it was hard to detect the brown unless it was in the sun and contrasted with a true grey. But ... I'm sure there are different tones one can choose that highlight the brown a bit more.
I have a very dark brown fresco (via Slewfoot) and a brown flannel chalkstripe. I also have greyish hair and a darker complexion. I really like them both and wear often (in season). I just bought some vintage John Hardy pinstripe/heringbone in brown and will have that made up later this year. I also have 4 brown odd jackets.
Check the WAYWRN thread today - I have posted photos of my dark brown track stripe three-piece flannel suit. It may give you some idea as to the final appearance of a charcoal brown suit (though my coloring and the OP's are quite different).