If you plan to use regular ice cubes and don’t want your drink watered down, make the tea stronger than you normally would.
Don’t use a powdered instant iced tea mix for this drink. You’re using amazing whiskey, and so you don’t want to ruin the drink with an artificial-tasting tea mix.
Toss in some fruit or different juices for unique blends of fruit flavor. Peaches and berries work especially well, and they can be added fresh or frozen before you blend the slush or added afterward for visual appeal.