There is no Starbucks procedure for light ice, it’s not in our training so everyone does it a little different

I usually put about one size less. So if I’m making a venti I’ll put almost a full grande scoop in.

For that Iced latte. I use 3oz of 200°F espresso and top that if with chilled milk. If you look at any starbucks cup, above that 3rd line (which is regular ice), there id a cup ridge. I pour milk to there then add ice.
For iced teas, build one beverage size up for the beverage. And one smaller size scoop of ice.

Like previously stated earlier, there is no right way. But the heat of shots really affects it. And iced coffees and cold brews are all different ratios.
✌💚😃

It’s not an officially trained thing, so every barista does it a bit differently.
Some baristas will fill their scoop up half as much, some will use a size or two smaller. It depends.