I found that it’s a bit hard to measure leaves. My suggestion would be to add as much leaves as you want. Or as little as you want. I don’t know about international but in South-Africa we can buy a pre-packed mix of assorted lettuce leaves, wild rocket leaves and spinach baby leaves. The packet’s name is Wild Rocket & Spinach Baby Leafs Salad. It comes in 120 g packets.
About the Apples:
We use Granny Smith apples. However, I know some people say that the Granny Smith apples are too sour for them. So if you don’t like Granny Smith apples you can buy one of the sweeter apple brands.