Hi Nigel,
Carbon is not really lighter. But far more reliable. And stiffer while sailing.
It depends how much you like swinming with your gear

Broke my last alloy boom 4 years ago, a few km out at sea....was lucky enough to be able to turn it around, but it took me ages to re-attach it and sail back very slowly....
Bought an AL 360, never looked back, even got another one !!