I was debating the white wall versus black wall this past week as I had to get the rear tire replaced on my Electraglide Classic.
Was gonna go for the black wall look but after sleeping on it, decided to stick with the white wall. It just looks better with the spoked wheels and tu-tone paint on my ride.
IMO, your Road King looks great the way it is. You may want to consider going with different tank emblems but to me, a fuel tank looks naked with out any logo on it.
I can see going without if you have a no-name or brand x bike but a Harley Davidson motorcycle should proudly display its logo on the tank.
I know its your bike and you want to personalize it somewhat but I've seen too many beautiful Harley Davidsons that have been "customized" and they honestly would look better and be worth more if they had been left alone in the first place.
If you want to try different paint themes, it might be worth buying a new tank and new set of tins to play with, that way you have the option of returning it back to factory down the road.
Just my 2 cents.