i checked the wiki subarticle "Consonants" and there is an example of /kar/ vs /ca:r/ (youglish link, as evidence for ":") which might not be a good minimal pair. do you know one? /g/ vs /ɟ/ would also work for me.
":" ruins it for me, because I consideer vowel length contrastive. "Karanın kası" means "the muscle of the land", but if I pronounce it as /ka:sı/, it sounds as if someone is dictating the letter k, giving "land" as an example word with initial k.