This beautiful punch recipe is from 1959.
Here's the Canada Dry recipe for party punch.
1/4 cup sugar
1 small jar (8 oz.) maraschino cherries
3 cups grapefruit juice
1 large bottle Canada Dry Hi-Spot Lemon Soda
1 large bottle Canada Dry Club Soda
1 large bottle Canada Dry Ginger Ale
Optional: add your favorite liquor to taste (gin, rum, whiskey or vodka)
Combine first 3 ingredients; pour over ice into large punch bowl. Add ice-cold soft drinks just before serving. Add liquor if desired, stir gently. Makes about 30 punch cup servings.
That's the official recipe. The photo in the ad includes lemon slices, which I would definitely ad.
Also, I don't think Canada Dry makes Hi-Spot soda any more, so you could substitute any lemon soda (if you can find it) or Sprite.
Last, the recipe calls for "large bottles" of the soft drinks. In today's world, that would be about 2/3 of a two-liter bottle.