Hey!
Currently doing drywall myself and I am using 6x6 cm squared timber around my outside walls.
The problem is they aren't as stable as the other walls inside the house because of the 6x6 cm squared timbers that are about 30cm distance from each other.
I will screw my plasterboards on the squared timber and only one plasterboard, not two.
I have two pictures of what my construction looks like from far and one from close.
Maybe someone can give me advice before I install the plasterboard onto it.
The only problem I currently see is finding the subconstruction once I put the plasterboards back on. But other than that, if I find them can I install the cabinets safely?
Behind the green board, behind the OSB, there is a very thick top plate that those beams are sitting on and based on what the OP said to me, that is then framed down to a sill plate also behind the OSB. Nothing on the outside of the OSB is structural and he's actually screwing those 6x6 cm boards into what's behind the OSB. They're using the OSB as a vapor barrier instead of faced insulation like we do and also protecting the studs with that vapor barrier from the interior of the house.
Edit: Truth is, what's funny about OP's wall and the response it's getting is that it's better constructed than most American buildings you could find. We don't tend to put as big a gap between the vapor barrier and the interior heated space and we don't tend to include the studs as protected by that vapor barrier. When we do we use plastic sheeting, not OSB, because that's too expensive. I'd imagine the R value on his insulation is also much higher than ours.