>>2938841
As an upgrade you can add a chaber with a high density (often PVA) sponge that doesn't directly touch the other chambers. By adding liquid to that sponge you can then hydrate the ytong stone.
Adding some plastic foil to the back is also a good idea, partially because it catches the small ytong pieces that fall off when you are moving it too much, but primarily to keep the moisture in. This reduces the times you need to water it as less water evaporates, and protects the wall behind the ytong from any moisture and mold.
If I do either of those upgrades, it'll be tomorrow though.

The grout nest is also still drying, so any further work on that will have to happen tomorrow too.