Well there are a variety of ways to make a high CBD tincture. We recently wrote an article on this topic:
I think the key is is if you are starting with raw cannabis it is recommended that you decarboxylate it as this activates the THC and CBD. After this, at least in our recipe we suggest that you leave it for 2-3 weeks in a cool dark place and shake it every now again.
Please know that you will not be able to know what your dosage is accurately from this, so start low and slow until you know how much CBD and THC works for you.
I am not a doctor and this post represents my opinion only. I hope this helps!