I did my AQC with an external chap, so he did what you're thinking of doing. He went into the hold pool mid-July, had an interview with Thomas Cook in October, didn't get it. Then he waited it out for easyJet and got the job in February. He'll finish his Type Rating next week. Just to give you an idea of time-scale.
It does depend on your performance during the program as to how quickly they place you. If you don't meet their standard to put you forward to easyJet then you could be waiting a while...if you perform well however, they will get you a job quickly. Lets face it, they'll make money out of you if they do.
Hope that helps a bit.