In the world of windsurfing, we all use carbon masts, of about the same standard diameter.
Thin walled 100% carbon masts cost up to $1,200 each, weigh around 3.5 lbs., have stiffness ratings the same as all masts, but reflex back to original form much quicker.
Thick walled lower content masts cost down to 170 bucks, weigh around 6 lbs., same stiffness ratings, and reflex back to original shape slowly for less response and quickness.
I'd guess we need to measure not only overall stiffness, but it's ability to reflex back to it's original form. Bigger diameter should be quicker.