good questions. I'd like those answers, too^^
Well it has been a few hours and no more supplies so I think I have my answer. Also the short duration of the event is a bit of a clue.
You do not get more supplies over time, only initial allotment and then purchases.
Spying is used to try and ascertain the movements of coin being transferred around. Being as you only see the 10 most recent transactions it would be almost impossible to get a comprehensibe list, but you may still see trends.
Honestly the spying is more for team play. If you dont care, I say just raid the vault.
So far what we've seen during the raids of the vault: Vault Loot Rarity
Hopefully we can figure this out.