Has anyone had any experience with NCX and a jp fsw102, I'm just wondering if it would be a good match

I would not go for it, except if you are running your fsw as a freeride with outboard straps and big fin. If you are into manouvres a freestylewave sail will be much better.

I stopped using the board with single straps as at 70kgs I always felt it was a bit big for me doing bump and jump, more so with a 6.5 . It feels better blasting up and down in the bay with outboard straps.

Next question, would my sails benefit much swapping from powerex Rdms to a gorilla mast, is there much in it?

If you're using the board for blasting around, an ncx should be fine.

i use my fsw93 with a Np hellcat 6.2 ( similar to ncx) when I need to give my knees a rest from the slalom board.

I use inboard straps and thruster set up, makes for a relaxed ride.

That's it then, just got to find one I can afford now.