It might be helpful to tackle the question '"What basis do you use for choosing?" by taking into consideration societies two greatest taboos... sex and death. At the risk of being blasted once again for using Osho as a source... he offers quite a bit of insight into this...
Sex and death are not only the two greatest taboos... they are also the focal point of all of the world's religions. They are also at the core of psychology... and they are the two key ingredients in any secret society!
By considering this at the most basic and essential level... it's easier not to lose the bigger picture by being overwhelmed with all the details... or get side-tracked by all the smoke and mirrors.