Once I pull the stats, I'll think about running the 2x upgrade kit drop event. Also, here's a snippet from a discussion JDario and I were having on discord:
The good part about this new system is that there are a lot more moving parts to it than just drop rate + stone upgrade success rate
So we can look at things like reducing the zeni cost to upgrade kits
Reducing the amount of kits needed from 5 to 4
Reducing the amount of crafting materials needed
Increasing crafting material salvage rate, making crafting materials drop from farming
These are the kinds of things we'll look at, rather than just drop rate or upgrade success rate