Hmm... What you've written about the public storage doesn't seem like a public storage, it seems more like a private storage... The point of it being public is that everyone can take what they need, and store what they don't need without consequences/fees/etc. Those are the rules for Spawntown's Public Storage.
You're still allowed to have some private property - 64 diamond, gold, lapis and iron blocks plus 64 gems, lapis ores and gold/iron ingots, 576 redstone dust and coal. (Even though it is the goal to make this public in the end too, and the same with the state property which you can also keep from the public storage.)
Currently I keep a system where I have a small amount of iron and gold in Spawntown's public storage, and if it runs too low, I put some more in there. That way you don't risk losing it all, but it is still public to some degree.