Try this on your sipping vodka.

[Rocky_Creek]

I calculated how much water I needed to add to some 188 proof vodka to fill a liter bottle and bring it to 80 proof. Instead of water I added Sam's "Twist up" a clear diet lemon lime soft drink. The vodka remains perfectly clear and has an interesting lemon lime taste when sipped straight. I may leave the lid loose to let the carbonation out, or not. Might add a pinch of sugar or not but interesting so far.