I'm just wondering how you decide how much to use of what (henna, indigo, cassia)

And when you are saying 1/2 henna, how much is 1/2...?

So many questions!
"Life is full of beauty. Notice it. Notice the bumble bee, the small child, and the smiling faces. Smell the rain, and feel the wind. Live your life to the fullest potential, and fight for your dreams.