How often should I expect to see strength gains?

[Arioch]

VDL, IMO, the single biggest difference between PL and BB training is the focus. If you are focusing on increasing your squat, bench, and dead, then this is what you focus on, not a bodypart. You do not train chest, shoulders, and triceps, you work to improve your bench, and the only bodyparts you focus on are the ones that are holding back a particular lift. This works pretty well for size gains simply because the vast majority of the muscles are getting hit pretty hard with compound lifts, the only ones particularly lacking in a PL program are usually the biceps. In a well designed OL program, the biceps should never be trained directly.