Everclear is great for topping tobacco. You can soak your natural flavorings in it, slightly heat them under pressure, and then mix with some distilled water to give the tobacco a new taste.
However, at this point, I am skeptical of anything but light flavorings, because unlike tobacco they can be harsh on the throat, and other than having the air be less stinky, really offer nothing much.
I like some aromatics, but have to dilute them with lots of Burley to avoid the negative consequences of the toppings.
However -- this is the whole point of this post! -- if you want to experiment with toppings, get some vanilla beans (Costco and Target have them) and soak them in Everclear for a few weeks. Mix 50-50 with distilled water and apply to a 3:1:1 dark burley, light burley and Virginias mix. Best OTC you never knew existed.