What density does it take to go outside on a bright sunny day and look like someone that does not have thinning hair?

I have medium to coarse dark brown hair with very high donor density. I'm not looking for total grafts but what density (grafts/cm2) on average would it take under those kinds of lighting conditions to not look like the sun is shining down on a see through hair transplant. My scalp is light color and I understand the contrast makes that lighting condition even more difficult.