I have made this many times and love it. The original recipe from Dr. Fuhrman called for 2 bunches of kale. I usually use 20-24 oz of kale for 4 servings. It gives a little more sauce on the kale. The original seasoning was Dr. Fuhrman's Vegizest which is what I use. It is a very mild seasoning which is why you use 1 Tbsp. If you are using any other salt free seasoning, I would suggest about 1 tsp. instead. Also, you can use other non-dairy milks. I use unsweetened almond milk.
I made this exactly as directed and it turned out pretty good. I will make this again, but I will cut the seasoning in half. I used Spike and that was about all I could taste in each bite.