@Noddykitty firstly there is a chemical difference between thc and thcv. Thca does not convert into thcv it converts into thc. Thcva is the carboxyl acid form of thcv. Thc and thcv have similar properties and effects but they also vary greatly and have different medicinal uses etc… thc is a pentyl carbon chain where as thcv is a propyl carbon chain. THCV is also federally legal and legal in 38 states where as thc is illegal federally.
Now with that said in order to answer your question properly I need to know if you want information on THC or THCV.
As far as the other cannabinoids and terpenes cold alcohol extraction is one of the best methods. It will not convert thca, thcva, or cbda without heat though you might still get some conversion because of age and oxidation before you begin the alcohol extraction.
For cold extraction with alcohol a minimum set time of 3 hours with agitation is needed. The longer you let it set though the more it will pull out. If you let it sit a long time make sure you shake it a bit and agitate it every day. Once it sets long enough to extract everything you can do a cold evap and filter process like what I do. Filter it into a clean container through organic unbleached coffee filters and let it set in a cool dark area and let the alcohol evaporate off until it reaches the consistency you desire.
My personal preferred method is to use a soxhlet extractor on low heat with non denatured alcohol 95% or greater. Just let it run until the drip runs clear. It operates at a low enough temperature it will not decarb anything.
As far as the medicinal benefits it all depends on the type of cancer and delivery method. Lab studies are great but it shows the effectiveness in a petri dish not in the human body. So it would be difficult to suggest which delivery method to use without knowing the type of cancer etc…
Sublingual dosing can be effective if you let it set under your tongue long enough to absorb.
Yes, you can make great tinctures with cold pressed rosin by putting the rosin in alcohol or a carrier oil. I do this myself with cold pressed fresh flower rosin on occasion.
If I missed something or anymore clarification is needed on your end feel free to ask. This is a good discussion to have.