I use 3 containers in ragged flagon. Never had a problem. Stuff always there.
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Hmm. That sounds safe enough.
I generally organize my storage so I would have way more than 3 containers in use (one for weapons, one for armor, one for alchemy ingredients, one for potions, one for blacksmithing ingredients, one for jewels, one for soul stones, one for jewelry, and one for food), so hopefully the other chests are safe as well.
I was able to do this in the Arch-Mage Quarters without any trouble while using every container available in the room.