Don't use more sweetened condensed milk than what the recipe calls for since it won't freeze properly due to the high sugar content.
The matcha will settle to the bottom of the ice cube tray as it freezes so seeing the gradation is natural.
The smaller the ice cubes, the faster they'll melt in milk.
Ice cubes will be good in the freezer for up to 2 months. After that time, the quality and flavor won't be as good.
To make an iced matcha latte, put ice cubes into a cup and pour milk (any kind) on top. As the ice cubes melt, the drink will turn into an iced matcha latte.
Instead of freezing the matcha latte into ice cubes, pour it into popsicle molds to make matcha popsicles.
To get bright green matcha latte ice cubes, you need good quality matcha. Look to spend $20 - $30 regardless of whether the package is labeled ceremonial or culinary grade. If you get poor quality matcha, the color of the ice cubes will be a dull green, almost brown.