I would go with even less - a 1% to 2% dilution is what I normally go for, but only after tasting the whisk(e)y neat. Some open up better than others with the a

I would go with even less - a 1% to 2% dilution is what I normally go for, but only after tasting the whisk(e)y neat. Some open up better than others with the addition of a few drops of water. For example, a particularly good Balblair whisky in my collection transforms into a sweetshop of flavours with a ~2% dilution.