ᐅ ESB boards, does anyone have experience with them?

Good evening, our carpenter is going to make the walkable area of the loft in our bungalow ("living space truss") accessible. The area measures 9.2 x 3.5 m (30.2 x 11.5 ft). Access is via a pull-down attic ladder, and this space will only be used for storage of various items. The carpenter suggests using 22mm (7/8 inch) ESB panels with a tongue-and-groove system as the material (more cost-effective compared to OSB). The insulation between the rafters is 24 cm (9.4 inches), and to ventilate the ESB panels, the carpenter plans to create a 4 cm (1.6 inch) gap using battens. According to the structural engineer, this area should also be constructed with 22mm (7/8 inch) panels acting as a diaphragm.

Who has experience with ESB panels?

The carpenter intends to nail the battens to the bottom chord of the trusses and then lay the panels crosswise. The truss spacing is 92 cm (36 inches). From my perspective, I would prefer to lay the battens crosswise to the trusses at a small interval, and then lay the panels crosswise on top of that. What spacing for the battens would you recommend?

Many thanks in advance!

24 cm (9.5 inches) insulation is a bit insufficient anyway. OSB is not an option at all because it is not vapor-permeable. ESB is somewhat better but only with a cross battens substructure for ventilation. Why not use rough-sawn planks?