Help! How do I ensure long play sessions?

As the title says, I want to be set up for all day play sessions. Every now and then I will have the opportunity to play for 9+ hours and am aware of the quest’s limitations with battery.

So what do I need? I will definitely need a kiwi head strap as after using PSVR I could never find another style comfortable. Do I get a battery kiwi strap and some portable power banks to store in my pocket? Will that even work without needing to take the head strap off? Or do I get the regular Kiwi head strap (without battery) and just get a few power banks? What do you guys do?

Appreciate any thoughts on this.