The typical heat and pressure of layup is 185C for 60 minutes with controlled ramps up and down.
Prior to layup, the prepreg is kept in cold storage typically @ 40F (5C) with less than 55%RH.
As far as bake-out, We established a 3 hour pre-process bake (it was an integrated process, we ink-jetted the markings, then used a long curing cycle to set the ink as well as provide a pre-processing bake).  Once we put this in place, we experienced 0 delaminations from moisture (we had been experiencing about 0.2% prior as a best estimate).

This included every conceivable type of PCB and thickness.

3 Hours @ 125C.  FR4 moisture loads pretty quickly, but also gives it up nearly as fast.  As for moisture retention, when cross-sectioning moisture delaminations, they were always on the outer sides of the ground layers, never between.  The primary reason for this is that inner layers are typically manufactured from 2-sided cores, where as the outers are applied as copper sheeting.  I would track down Jim Monarchio from TTM for a more definitive answer as he is probably the best technical guy I know.