In the directions that I've seen, you only want to cross the belts if the attachment point is quite far back from the shoulder. I don't remember what the spec was, but if the belts are attached to the cage crossbar right behind the seat, you don't want to cross the shoulder harnesses.

Shoulder belt mountings located more than 200 mm [8”] from the back of the user’s seat or angled upwards are not good restraint practice and are most strongly discouraged. If longer belts are used, the inside edges of the belts should be still closer together at their mounting points, even touching or crossing, but both belt and HANS® performance are severely compromised.
Shoulder belts should be crossed when the anchor points are more than 500mm [20“] behind the seatback.