Theoretical chance system:
Base chance of DClone popping in your game when the global even triggers: 0.5%
That’s one in every 200 events. Or a single DClone spawn per account every 15,000 to 24,000 (19,500 average) global SoJ sales.
If you sell SoJ’s, you not only contribute to the next event, but you also boost your chances:
If you sell 1 SoJ, the base chance is doubled.
If you sell 2 SoJ, the base chance is quadrupled.
If you sell 3 SoJ, the base chance is octupled.
Selling 8 SoJ’s would guarantee you DClone to spawn. (128%)
You ride the percentage chance until DClone shows up in your game. Once DClone pops for you whether it’s the next event, or 5 events from now, the chance is reset back to 0.5%. Not being online or not being in a Hell game during an event doesn’t negate your chance, you’ll just have to wait until the next event happens.
It’s just an idea to demonstrate the mechanics, the base chance could be raised or lowered, the chance multiplication per SoJ sold could be increased or decreased, the chance per SoJ could be additive, etc… However I think selling 10 SoJ’s should be the maximum limit on how many guarantee a single account a 100% chance for DClone to spawn
Bringing the base chance down to 0.2% with every SoJ doubling the base chance would require 9 SoJ’s for a 100% (102.4%) chance of a DClone spawn.
The base chance being one in every 500 events. Or a single DClone spawn per account every 37,500 to 60,000 (48,750 average) global SoJ sales.
Edits: More details, corrections.