Has anyone bought:

A) King size shikibuton ?

Q: Was it cumbersome to roll up and store away or for airing it out / cleaning ?

or

B) 2 Twin XL size shikibutons to form a King ?

Q: Was the seam between the two futons noticeable or uncomfortable when sleeping with a
partner ?

For Either: Would you purchase this again ? Or what would you recommend ? 3" or 4" thickness ?

A little background:

I (31M) just moved into a new 1 bedroom apartment. I have moved many times and have come to despise mattresses due to their bulkyness, cost, and difficulty with reselling or disposing of them. I'm living alone but have a partner that lives separately in her own apartment and would like us to be comfortable when she stays the night.

TL:DR:

Seems like 2 twin XLs would be great for its modularity, but Im worried that the seam between the two futons would be uncomfortable. A king sized would be great and comfy, but I'm concerned that it will be difficult to roll / fold away, or hard to clean.

We tried sleep training and decided it wasn't for us (but still zero judgement for those who do it, and I'm not willing to argue with anyone here about it) so we will be continuing to co-sleep.

Because of this, our queen bed isn't going to work for our family anymore. My husband wants to buy a king, but I'm curious about a Japanese floor mattress instead. He said he could be game. I like the idea of being able to roll it up and put it away during the day and have more space for *activities* during the day

I also like that they're available made of more natural materials and much less expensive than a king sized bed.

Anyway, anyone have experience with this? Brands you like, how was the lifestyle change etc?