Important disclaimer: all of the chances used here are taken either from NCSoft Korea's official announcement here, other official posts from KR provided to me by 4r4m, or Experiments performed by Innova Experiment Team. Korea is now legally obligated to provide real chances of any RNG they use in their version of the game. There is a possibility that different (NA/EU/RU) versions of the game have modified values of these chances. You can guess which is which by the text on pictures (KR/RU).
Disclaimer 2: all of the values here were calculated using pure maths and statistics, and give the average values. If it says that for example you need 1200 boxes for a Jewel 6, it means that some people will need 600, some 2k, but if you added up all the people that ever tried, 1200 would be the average value they needed.
Disclaimer 3: any prices visible on the website are taken from Innova Core server, on the day the event was introduced into L2Store.