I am going to have 4mm plywood with a lasered finish on the walls in a small office. Behind this, there is OSB. Between the plywood sheets, I have a 4mm gap so I have some leeway when cutting.
But how should I best attach the plywood to the OSB? The easiest is to hand-nail it with brads. The heads disappear into the grain and the lasering. I'm a bit unsure if the sheets might start to warp over time. That's why I'm also considering combining nailing with gluing (like construction adhesive?). Or is there a risk that the glue might make it worse?
What do you think will be the best and safest approach?