hey Watts...long term or short term storage of fine or cheap cigars would be considered as 70-72% RH but most prefer somewhere between 62 - 68% RH (personal preference)
http://humidorsforless.ca/faq.htm a cigar website talking about humidors
I have heard of a few that store at 60% but anything lower would be non-conventional. Temp is critical because of tobacco beetles which can hatch at about 70F.....this is not a concern for MJ.
I store my cigars at 65% and my mason jars at 62% but this is more or less as it's not easy to maintain an exact RH and/or temp