I have tried many sail on many mast and many mast on many sails and nothing compares to the correct one ,
i found North now Duotone the fussiest to match other mast ,I'm not surprised the Naish mast was awful .
I think you need to go back to NP .

or buy a duotone mast ,
being a larger sail it will be the mast that is the feel .I am lucky I was a North man and kept my expensive north
masts as they work well with my ezzy's but never had luck with mixing NP with North ,they always feel average .
Rigged ok but felt sheet to sail especially in the gust ,just warping out of shape ,the NP mast where just too soft .
I just couldn't get any drive out of the north using NP either ,so how much you want for it ?