Since I didn't see this covered in this thread, for materia infusion purposes the Omnilex (And presumably the Thyrus) count as already having 9 grade 1 materia infused in the scroll. So you infuse 2 grade 1 heaven's eye materia before it moves to needing grade 2, but you do need 11 grade 2, 11 grade 3 and 11 grade 4 materia to complete capping out the stat.