I do have this problem every damn year, yet the weather generally relieves me of making the decision! Just worry about waterproofs and you'll be ok!
Seriously though, I can never get it quite right, and tend to only dare to wear the tights or hold ups in evening as broad daylight makes my legs look prosthetic/mannequinesque in them. Very low denier black are ok for British summer, but I've got to the point where I just try to find knee length skirts and dresses and go bare with a smidgen of Dove glow.
I find a light sheen looks more natural than dead matte. I got some f&f sheen tights in tesco in natural tan and several people commented how nice and tanned my legs were and really didn't think I was wearing tights. Am sure they do hold ups in same range.