I spent 8 weeks at dust devils, i didnt get anything good after updates.... jsut average drops..... i spent 2 updates ( not the whiole 2 weeks ) at metal drags... average drops... Jagex said its based on 2 wheels, 1 with rares ( gems, half keys and anything else the monster may drop.) and a common wheel ( coins, runes, common objects etc.) When a monster dies one is spun ( with a higher chance of the common wheel being spun) each item has a certain ammount of slots, for example - for dust devils if you get the rare wheel, chain will have lets say 1 slot, but a sapphire would have about 50. A ring of wealth just increases the chances of spinning the rare wheel. This is what Jagex themselves replied to a message sent to them asking how the ring of wealth works, if i can find the screeny again i will post, but it was a month or two back.