I haven't paid attention to harshness vs tint of juice but I do use different power and or temperature on different juices. The degree of harshness for me usually comes down to the nic level I'm vaping.
What is the desired amount of nicotine when you're going for? In other words, when you buy premade eliquid now, how many milograms of nic do you get? I'm vaping 3 mg of nic now so even 1 drop of pure 100% nic inside a tank would probably be too much for me. YMMV