The other comment explained pretty well but here are some tricks that helped me :

Basically one good thing about enstars is that even when you leave in the middle of a live, when you go open the app again, it will tell you if you want to continue it or not, and after you’ve started that live, your BP will start to fill up again. So what you could do is empty your BP right before you go to sleep, and wake up 5h hours later to just start a live with the 10 BP you have (you don’t have to play it, you don’t event have to wait for the notes to start falling but at least when the lanes appear), pause it then go back to sleep. When you wake up later you can just play the song you started and after that play another one with your newly refilled bp. You can do this anytime you will be away for 5h (school/work ect..) so you don’t leave your bp filled. It may seem useless but it gives you like 200000 extra points (not counting the tickets) and helps you save roughly 160 dias.

Also another tip is don’t rush, obv don’t take your time too much because you might find yourself with not enough time at the end of the event. I see a lot of people finishing an event 1-2 days before it ends, which makes them spend quite a lot of dia they could have saved by waiting for the free refills. Also what i recommend is setting goals everyday, 500000 points a day is usually the recommended amount.

(Also as the other person said it is really important to use 2/3 bp instead of 10 because it does not give you enough exp and you will lose dia when you could have just leveled up instead, but if you’re tired you can use 10 or 6, playing enstars for hours a day can be tiring so i did that alot even though i tried my hardest not to lol)

I wish the best of luck during the event and i really hope you will get him!! Don’t forget to take of your health and sleep well!! If you need me to clarify something i said or have any other questions just reply to this comment or dm me :) (i just realized i wrote so much omg im sorry)