Broke my last two booms which were in carbon; just switched back to alloy.
Alloy booms rarely breack (even though they can bend a bit..) and now have 26mm diameters and are pretty stiff. Maybe not as good as carbon, but for the price of one carbon boom you get 3 good alloy booms.. good for 10 years of sailing. I d rather spend more money on the mast than on the boom..
Sorry, did not answer the question..