>>529754830
>Yes, you only need to cast one EX per 30 seconds
With Kaboom, that's not enough to reach that.
If you give Yuziha Bashful, it will only be enough for 1 EX every 50 second.
If you give her Kaboom, you get 1 EX per 40 seconds. That's walking on a tightrope, always stressing out on her EX meter.

Unless you go for
2piece Vivian disc
2piece Swing jazz
2piece ATK disc
Then you can get 1 EX every 29 seconds.

Use Qingyi's engine on Jufufu if you have it.
It's her best in slot while retaining flexibility with many agents.