I suggest you get in touch with the company that Andreas recommends in his book, and buy the pre-mixed
herbs from them. That's what I did. Very easy and
not overly expensive.
It's a small company called The Present Moment in Minneapolis. Their website is: http://www.thepresentmoment.com
Their phone # is 1-800-378-3245. They sell a big batch
of the pre-mixed herbs for about $25.00. I don't know
whether their Cat's Claw is from the bark or leaves.
You could ask them.