I insulate a house from the profiled beam with a ventilation gap. Cladding combined plastic panels + metal siding. Mounting on a metal frame, which has already been deduced by laser. Joining the plastic panels and metal siding with H-shaped metal strips. The thickness of the panels is 27mm, the thickness of the siding 22mm. The H-bar is made with a slot 27mm on both sides. Can you advise what can be put between the metal framing and siding to compensate for the 5mm difference? I am thinking of cork underlayment, styrofoam.
You can attach the H-profile through a strip of OSB or plywood of suitable thickness, so the eco-board will be adjacent to the outer edge of the profile.