Now i had time to do some thinking and a few problems seems to grow:
1. they started to back down on the last day which is pretty bad. earlier got some back down after a few weeks which speeded things a lot.
2. Great Quing is not fighting so for the past 15 years i got 3 states from them, 65 years left that means 13 states, it may be possible to puppet them towards the very end but it's not ideal
will see how it goes next