I do not grow lowii, but if I did, I would be growing it in the same conditions as my other highlanders, that includes hamata. To me, a baby plant is any plant 3" or under. They will be bagged up and slowly acclimated by snipping the corner off. Plants over 3" are generally fine to acclimate on their own. Besides, your humidity is not that far off of ideal. My hamata I just received will be slowly acclimated via the bag method mainly because my humidity is less than ideal.