I been in the cargo business for quiet a while...and had send turbines from down here to CA, about your same trip.
I do not consider the original jetcat packing quiet adequate. Instead I wrap the turbine with 1.5" cushion mat like the ones use to make sofas....about 2 laps or whatever it takes to avoid the turbine going loose in the box.
Then some tape to avoid unwrapping.
The width is about 4 inches larger in each side of the turbine.
I always use DHL...and the cost of shipping a ~12 pounds volume/weight box is around US$60 from here to CA. Insurance never exceed the 1% of the value insured.
Good luck