In my bartender’s class, we learned that the shape of the ice makes a huge difference on the cooling effects of a drink. What you want to do is have the lowest surface area to volume ratio you can manage (the ice melts the slowest that way, therefore not diluting the drink, thus a way to satisfy the most discerning customer). The greater the number of sides, the lower the ratio, until you get a spherical ice ball - that’s the lowest of all.
My neighbour has an ice tray that makes little ice balls - he’s way ahead of the game!
