If you belong to any professional herbal groups on social media, that is often a good way to find someone with a niche in this area. Additionally if you are a member of the AHG they have a number of informed consent/disclosure documents available on the website.  

Here is the link, but it may only will work if you are logged in as a member: https://www.americanherbalistsguild.com/ahg-mentorship

Another thought would be to engage with regional alternative health groups - if you want someone local to you, perhaps a lawyer who has worked with chiropractic, nutritionists, massage therapists, etc. If working locally they might be the lawyer's first herbalist! Oftentimes there are many healers network types of magazines and publications and groups that post/ connect per area.