As a cosmetic dentist, doing lip fillers, I always assess the filler when smiling.you sent that photo which seems to show exactly what appears missing..IN A SMILE. I think even less than a .5 ml would do the trick. if you like the fullness of the upper, its a little too large, in my view, then add to lower to get more in the lower.I would also dissolve a little in the upper to get a better ratio. To get a nice ratio , by starting out with an overfill un the upper, you are chasing the wrong thing. the good ratio of upper to lower with what you have already on the top, throughs everything into the TOO BIG range and looks clownish rather than a nice enhancement.i would dissolve a little of the upper, and add to the lower, for a beautiful ratio and smile enhancement.