Alright, thank you very much for the information!Two ways. Only one gives a definitive answer. Have them lab tested to verify. Or, talk with the breeder and see if they can give other phenotypic characteristics that correlate with high CBD levels. This is not guaranteed to work though.
I'd suggest get a pack or two of a couple strains you're interested it...run them and pick the one(s) that work for you. Then it doesn't really matter what the THC and CBD levels are...as long as it provides you the relief you seek.