For freeze-dried food products, with long-term storage being the goal, it seems to be all about controlling oxygen and moisture within the packaging.
It appears that the industry standard is to use very thick (5-7 mils) Mylar, which has extremely low oxygen & moisture vapor transmission rates. Coupled with an appropriately sized desiccant & oxygen absorber, this will handle any oxygen or humidity that is present in the bag once sealed.
My question, though, is; Can a thinner bag with higher oxygen & moisture vapor transmission rates achieve the same shelf-life if compensated with higher capacity desiccants & oxygen absorbers, and/or gas-flush sealing?
If so, how would one go about calculating this?