shogun89 makes very good points but do not get too close to the dew point for you area. this will for shore grow mold. it is a bit more complicated than just 70/70
i always watch the temp and do not drop it to the dew point and the higher the RH the easier it is. at some cases dew point can be influenced by barometric press. so if you can take all of this in to account then you will be ok. i keep my stuff around 35-45 RH and temp @ 75 deg F.
also i have been told to keep shu away from sheng. i do not know the exact why but i do it.
P.S the higher the RH the lower the temp the closer to dew point you are warmer air holds more water and if you decrees the temp the water has to go somewhere and if the bar pressure goes up temp increases so if it goes down dew point can be reached without changing temp. i needed a weather man to teach me this stuff i hope i learned good.