One thing I would add to DL's post. It is possible to trade training dates in our system. For example I have a friend who moved up his MD-11 upgrade class by about 8 months. Granted he is at the bottom of the list and will be for a looooong time (he lives in Collierville).

The upshot is that a relatively new guy could bid the 75 left seat and be in training fairly quickly. The training letter is just a starting point.