up, bump them up. if I deal with an RI I generally push my humidity to 70-75 and my hotspot to 93ish, and my ambient temps to 82, not out of control hot or uncomfortable.
a culture is something the vet will do with your snake to determine the type of RI it is if it indeed a respiratory infection. They can be bacterial, fungal or viral so its wise to determine what you are dealing with in order to treat it, as a fungal or viral infection cannot be helped with antibiotics.
A lot of vets just assume they are bacterial and treat accordingly, and in general they usually are, but its always better to be safe.
Do you see any bubbles coming from your snake's mouth or nose?