Not really sure why some people can build up a tolerance quickly and most cannot. I suppose the liver could have something to do with it. Going through the RSO procedure is not easily done. It will be difficult. I prefer using a full spectrum of strains, and those strains are mostly high THC. If I were to focus on adding a high CBD strain, I think I would choose Tora Bora. I have seen a lot of test results on that strain and it is very high in CBD.