I don't think there is a way to measure the dynamic spine of an arrow.Like your Carbon Express 350 at say 29" is going to be the same static spine as a 32" 350.But the dynamic spine will change as you shoot them with adding weight or shortening the length.A CX 350 has a .320 spine and will take alot of weight to tune it in most likely.But you'll need to shoot it,to see how they are hitting the target.I have one bow that I shoot a Beman Black Max 300(.300 spine) with 100 gr. insert and 200 gr. point and they fly great,this is from a 70#@27 longbow.200 grs. won't hurt your shaft but a 250 may be a better choice.Is your bow a recurve or longbow? How close to center is your bow will have an effect on the dynamic spine in tuning.How long are the 350's? A 2114 has a .510 spine and if they are flying great,the 350's(.320 spine) may be alittle stiff unless the are long enough to weaken the spine with a heavy point.But you need to shoot them to find out.