not a CX shooter, but youll want a 600 spine arrow with light tips (80-125gr) or a 500 spine front loaded with 100 gr brass inserts and play with tip wgt.

with carbons, ALWAYS leave them long and cut to tune. A half inch change in shaft length can have rather dramatic dynamic spine effects. remove a quarter inch at a time from a bare shaft till you get the flight you seek. It has been my experience that longer is always better when it comes to carbons. ymmv