The thing to remember, here, is that all wood species take to drying differently.......and any single example of any particular species will react to rapid drying differently than others. The general rules will apply, but those rules will need to be modified as individual blanks mature. Cooler temperatures are your friend!
Generally, you are better off to allow lower processing temperatures, and methods of slowing it down to work, rather than to dry your roughed bowls as fast as can be done.......I know that sometimes this is hard for us to do, because we are anxious to get on with it.......but patience is a virtue in pursuing this venture.
Consider this: If you develop cracks, slow down the drying.......period! Always use a method of slowing down the process. There really isn't any other way to control drying checking. Time is sometimes difficult to accept, but the ONLY way by which one can master the technique.
Personally, I wouldn't keep unwaxed (or, wrapped) bowl blanks for more than a few months......but, like I said, all individual bowl blanks may be different than others.........there is no single rule that will be universal.
otios of cologne