I'm no expert or anything, but um I'm not in a medical marijuana state either. If your who I think you are, you already know this..... But ya I'm no expert, and the whole percentage thing was strange to me also. So what I did was, use common sense when I put mine together. When I found out the strain name, I would Google it. I would then read how much THC it had, was it sativa or indica? Or in most cases nowadays how much of which? Was it a sleepy high, energetic, creative, etc.... What symptoms did it relieve? Pain, spasms, Bipolar disorder, stress, add, etc.... Then you think in your head hmmmmm, I got allot or a little of these symptoms. I do want energy, not so much that, I can't sleep or my hearts pounding, and you rip off a chunk more or less according to your needs you want to be able to function is your goal, if you just want a buzz that will fuck you up don't waste my time,.,, you can go look that shit up elsewhere