With an American Wheat, I opt for a malty profile so that I can emphasize the wheat character and minimize hop bitterness sensation. The absolute 'Best' water profile is really dependent upon what you are looking for in your beer as far as aromas and taste. In general, I am using hop varieties that give me fruity or floral aromas, so I like to pack them into the whirlpool and get taste and aroma without the accompanying bitterness. Your goals may vary from this.