By pleasant coincidence I got a pair of ice ball molds for a birthday present. Tried one out with some rye whiskey. Worked fairly well, but still watered down the drink too much at the end for my tastes. Will try with a rum and coke though, as that should keep the drink cold but not as watered down as smaller cube ice.
Looks awesome for a presentation though, the wife is anxious to try them at a party