Paper thin cotton batting oriented in 90 degree offset layers is used for authentic Japanese futons. That would work.

I've actually gone the latex route for my living room sofa cushions, and honestly, it’s a total game changer compared to standard foam. It holds its shape so much better over time and doesn't get that annoying "saggy" look after a few months, plus it feels way more supportive without being stiff. If you're planning on keeping the piece for the long haul, the extra cost is totally worth it because you won't be dealing with constant fluffing or having to replace the inserts every couple of years. Just make sure you get the right firmness level for how you actually use the couch, since it has a bit of a "bounce" that some people aren't used to at first.

@Svetozar Zivkovic thank you! the latex is already purchased so thats set! Can you share what else you used with your cushions? what kind of batting did you use to wrap the latex?

First, I will tell you that there is no such thing as 100% Natural Latex cushions, whomever told you that is incorrect. Pure Latex will not hold together, it requires a chemical binder to prefect it from literally crumbling. The most natural latex on the market will be appx 93% latex, 7% binder agents.

Wool is used around latex in bedding as a fire retardant instead of Boric Acid. This is a requirement in virtually every state for mattresses, you don't need it for your application. Go with Dacron is my suggestion.

@The KEEPING ROOM are there more sustainable Dacron options available? non toxic , no fire retardants etc ?