Pontius,
Very good issues you've raised there. When I last did OASC( 1997), I was offered the chance to go NCA, in my youthful arrogance I basically said F**k OFF!, who wants to do that!! Oh how the tables have turned!
As I mentioned before, WSOp(EW or ACO) was just a thought bearing in mind my "trade" in the RNR. I would be happy with any WSOp role. All I can do is go back to OASC try my hand at the aptitude and see what happens. How different is the selection for Officer and NCA? Should I focus all my efforts as if going for Officer? Should I aim for Officer standard although going for Sergeant?