Originally Posted by qasr
Use the itin that they provided. Rocking the boat before you even get an interview is not in your best interests.
Agree here.
But you may want to figure out which FF program to put the DL miles into. If you expect to do a lot of west coast flying, AS is a good secondary program for mopping up non-*A miles, since DL, CO, NW, and AA are all mileage partners with AS.
On the other hand, if you do end up working there, you may end up flying on DL a lot, which may make its program more attractive than the partner programs (DL partners with CO, NW, and AS, but not AA).
Of course, if you already have mileage in an account with DL, CO, NW, or AS, you may want to keep concentrating the mileage there.