i think it is inevitable DEfos will be required for the above A330 expansion reasons. they did this as early as a year and a half ago...and very badly in some instances in that some of the f/os they brought in didn't even have the experience other f/os in the company already had.
i hope this will be done ONLY after every possible option (and prospective line f/o) had been looked at.
in all fairness to gf, fleet expansion cannot be slowed down due to lack of experienced pilots.
a problem i foresee is a lack in experience of f/os in seniority number 80 onwards, hence the possibility of the need for DEfos in the interim for the big busses.
the company would be wise to consider the repercussions of resorting to DEfos. a good compromise might be to have them employed on contract with a clearly defined end period.
i think at worst, using DEfos may set back progression from the 320 to the 330 by around 10 months.