I calculate how much I use of 100mg nic for 3-6 months, and then decide upon that form-factor for the entire stash. It may fill some more, but it's very nice to always just be able to pick up a rightly sized bottle for the job, without needing to redistribute and refreeze again. So in my case it's 100ml amber glass bottles, and which are aprox. 11cm high and 5cm in diameter, so then I go hunt for correctly sized plastic freezing containers for food and leftovers, and with a sealable lid, so that when the lid is on, then it practically rests upon the top of the caps of the bottles, and it would be best if room for a layer of bubble-wrap or maybe just some folded up toiletpaper in the bottom and top of the box + between the bottles. In each of these small freezing-boxes, there can be about 1.5L i.e 15 x 100ml bottles, and then several boxes can be used for the complete stash, to make for a better tight fit in a freezer, as can be distributed around where room available, or of course bigger boxes can be gotten... Of course for the people which have stashes of many liters, then I fully understand that this isn't optimal though... Also each bottle would be nice to be in it's own thin sealed plastic bag also, for containing/reusing spills if broken. Not as important if in a sealed plastic box, but vital if not and e.g. just in some bubble-wrap, so the nic dosen't spill into the rest/bottom of the freezer.
@sofarsogood, cxtc has a faq section with this question and they recommend there users using glass bottles with their nic to "purchase from any grocery store's wine section a product called Cork Pops. It is a Argon 5.0 injection system that can be used to blow out air ingress caused by opening the bottle, purging the air with pure Argon."
They state argon 5.0 is the best "push gas" type for extended nicotine preservation, as it's fully not interacting to the nic in any way...