How's old is your bunny and how much does she weigh ?
Kale is my girl's favorite and yes, you're right about the amount.
I feed my girl both pellets and greens. She gets greens for dinner (1 time daily), so when I give her green, I give her about 2 cups (400-450g). Due to her weigh (3.3 kg) and her age (a year and 4 months).
As for Kale. give her only couple torn pieces of it, that will do.
How about parsley ? It's easier to feed them with parsley 'cause it contains vitamin A and won't accumulate toxic , like kale or spinach.
Carrot tops, cilantro, bok choy, beet greens and radish tops are good choice as well.
*by the way, is that her on your avatar ? How cute !