Numbers
I would speculate that the Vigilant is going to be controlled by the servisable engine parts avalable, the Viking is most likely to be in the high 70's.
I am told that there are some airframes that the current contractor considers damaged beyond economic repair but the new contractors may view this with a different eye, so in the long run if money is avalable there may be more Vikings. However the aim is to get the largest number of aircraft into the air in the shortest time so I guess the least troublesome airframes will go down the line first.