I freezer-stash 30ml bottles just because I use so little, and make so little at any one time, and I don't want an opened bottle to be opened over and over and over and over... by using out of 30ml bottles, it's used up before it has much of a chance to oxidize and degrade. But i still keep my opened bottles in the fridge, just to keep them from light most of the time, and it keeps it out of my way, in one of the shelves in my fridge's door.
It's also easier for me to stash smaller bottles; the boxes that a dozen 30ml bottles are shipped in, fit perfectly in the bottom of my freezer, and I stack them, with the boxes numbered so I know which is the oldest.
If you make large quantities of juice at a time, and use a high mg level, then sure, half liter bottles are probably fine, provided you have sufficient space to stash bottles that large in your freezer. Personally, I think the argon gas may be overkill, but whatever floats your boat.

I don't worry about luer-lock caps, just because I stash such small bottles. Two different ways of preventing excessive oxidation in a bottle that's being used-out-of.
I buy such small bottles because I don't have a great deal of disposable income at any one time; the VapersTek TH nicotine is the best price I've seen on small bottles, $10, and that's an easy amount for me to come up with, nearly anytime. That way I also don't have to buy too many 30ml bottles too often. My stash is incremental, starting in the summer of 2014, to the present.
Andria