Thanks for your message. Like Mike, I have previously had forum posts removed for mentioning cannabis, which stifles any debate - at least this post hasn't been removed (yet)!
I agree that more research is needed, but unfortunately this isn't going to happen whilst the plant is illegal and considered to have no medicinal value. The real risks that you mention (discussed as side effects in the blog) are significantly less damaging and unpleasant than the documented side effects of prescription meds for PD.
The evidence of its effect on tremor, dystonia, muscular pain, neurological pain, mood and anxiety may not have been published as a result of any study (at least, not in the UK), but have been experienced first hand by me (and many other PD patients) which, to be frank, is good enough for me. Just like prescription meds, cannabis doesn't work for everyone - we are all different.
A video showing the difference that cannabis makes to my tremor (and thus to my quality of life) can be seen here - https://www.youtube.com/watch?v=JKvgIH6Tydw