When your horse has a glorious, tight, shiny summer coat, it IS spectacular to actually see their true, rich color and natural shine. Not every mini has the coat, but when they do, we should show it off!
I do virtually the same as Andrea. Shadow and light are your friends -- under chin can be clipped close without fear of color variation, as it will always be seen in different light and shadow than the other planes of the face.
With Mingus being a bay, I like to get rid of any mealy toned hair on his muzzle, but that's easy with normal clipping. With bays, you have to be careful clipping the coronet/pasterns lest any grey skin show through. You may need to touch up a bit with a black eye shadow crayon.
I couldn't do the "V" thing if I wanted -- with Mingus it sheds out completely along with the rest of his coat, so no subterfuge.
Be sure to use diet, supplements, lots of brushing, minimal bathing, etc., to keep the coat at it's peak.
Here's a not-very-good photo of Mingus in his natural summer coat, with only minor clean-up.