quindici
In my opinion any commercial experience, including flight instruction, would be more benefical than flying trafficwatch for more than 5-10% of your 500 hours total.
As a flight instructor you won't just do instruction as photo flights or tourist flights will form a part of your weekly work. As the NR Fairy said it is very important to show a broad spectrum of flight experience in your 'limited' flight time.
You say your intention is to gain 500 hours and gain work as a co-pilot. But if this hole disappears what is your intention then?? Have you a plan 'B'.
I don't believe that a previous life as an accountant or anything else shows that you would make an excellent co-pilot. CHC Scotia failures during training are testamount to the difficulties of finding the correct people.
So IF I was looking for a new hire with about 500 hours I would be looking for a little more than someone that had purchased their flight time doing trafficwatch.
Have you considered tuna spotting work??? Or is your goal to be a co-pilot in the North Sea??
With a civilian background myself, I do feel that flight instruction started me in the right direction so I maybe biased in my reply.