Hi! I'm an NC 44-45 usually the latter. I think one of the most important tricks I've learned for anyone with tan and darker skin with serious under eye circles is to always use a PINK undertone concealer to avoid ashiness and greyness. Even if you're already pink toned use a pink based concealer. For example if you're NC 45, go with a NW 40 or so concealer. NC 40? Go with NW 35 and so on... If anyone wants to see a comparison pic of using a pink based to yellow based concealer on the eyes, let me know and I'll update this =D.
Color cosmetic wise I own alot of different brands and products so just give me a category and I'll be happy to list my favs. I like bright and dark colors the most.