If that doesn't do it I'll try the stevia.
The cotton candy is a flavor, not a sweetener. Stevia and sucralose are sweeteners, not flavors. I concur that it sounds like you want the sweetener.
I use stevia, but I prefer sucralose, because it's more concentrated.
I couldn't find any stevia liquid that didn't have a lot of other things in the ingredient lists as well, but I did find a powder. Safeway brand stevia, believe it or not, is the purest thing sold in any store where I live.
I prepare it by dissolving 4g (2 packets) of the stevia powder per milliliter of boiling water. mix well until there is no powder left, then let cool. A tiny powder may precipitate out as it cools and settle on the bottom. I then pour the cooled liquid into a container, being sure not to transfer any precipitate with it.
I usually find that 5 or 6 drops in 6ml of liquid does the trick, but it can vary.