Hey guys, I was wrong about Qingyi's engine being best for Jufufu.
Jufufu does a free basic aftershock every 4 seconds, but the stack only last 8 seconds.

1 minute into the fight I thought we would be at 15 stacks:
_4 _8 12 16 20 24 28 32 36 40 44 48 52 56 60
_1__2_3_4_5__6__7_8_9_10_11 12 13 14 15

But I forgot to subtract the stats that expire every 8 seconds, so it's more like this:
_4 _8 12 16 20 24 28 32 36 40 44 48 52 56 60
_1__2_2_2_2__2__2_2_2__2__2_2__2_2__2
Her Basic aftershock can only maintain 2 stacks, and you need 30 stacks to fully use the engine.