Here's the information we have on seeing a dysautonomia specialist. The hospitals listed are the ones with full clinics that have sophisticated autonomic testing equipment not available at other hospitals:
http://www.medhelp.org/health_pages/Neurological-Disorders/Dysautonomia-Specialists/show/717?cid=196
Well, that is a complex problem! The only suggestion I have is to try Mestinon. It's a cholinesterase inhibitor, so it keeps the acetylcholine at the receptor site longer before it becomes cholinesterase and is no longer active. It also may be easier to regulate your dosage this way, as herbal preps are often not consistent in strength, unless you've got a compounding pharmacist or excellent herbalist preparing it fresh just for you. Mestinon is becoming more widely used to treat dysautonomia now, which makes sense, because it is the main neurotransmitter, along with norepinephrine. It has been used for many decades, so the side effects are well known. It can, however, make people sleepy, so you may have trouble with that. I find I'm very sleepy when I increase doses, then it goes away over time.
Have you ever been checked for autoimmune diseases? Chemical sensitivity is quite common with an overactive immune system.