Both..
Hunter used to offer standardly the fully battens main on their newer (about 93 and up) mainsail, very important to support the very roachy main , the main 'engine' of such-B&R- rig configuration .Lately they moved to partial fully batten: the upper 2 fully battens , the lower ones (mostly , additional 2) partial lenght ones .The later , I think ,is a good compromise which still retains the most of sail shape, but makes it eassier to handle the sail.This issue is less cardinal-but still beneficial- if your main is not the biggest sail of the two , or if it doesn't have a significant roach.Even so , to improve racing , I will gofor the second option ; it can support a sail with more roach than your present one ( but always limited by your backstay position..). this roach benefits are a) more sail area b) better airflow on the sail , especially on beating.Enjoy your new sail.