xnr,
All our pilots whether co-pilot or captain are trained to the same standard, we can have a captain-co-pilot crew, a two captain crew, or a two co-pilot crew in the simulator. We spend around 12 hours covering training and check rides and all are checked in both the right and left seats i.e. as pilot flying and as pilot non-flying. All the young co-pilots are missing is experience.
We don't fly legs, instead we do a complete flight and then swop seats and for offshore work whoever has the best approach and go-around carries out the landing.
As far as worrying about low time co-pilots making the decision, I really don't feel it is a problem. If they see the lights you can continue, if they don't you can't.
Or am I being too simplistic.