Hi TM,
I think we are starting to split too many hairs.
I think most of us are generalizing on this thread—we are thinking big picture. There are people who can make 1000 dives and still scare the crap out of most of us. And there is the person who can take some training, gain some varied experience, and be incredibly good, and safe, with only 40 dives.
A person who has been surfing weekly, winter and summer, will probably take to SCUBA much quicker than a lawyer from South Lebanon Ohio.
Generally speaking, I think a person whose aptitude is compatible with diving and the ocean, can become competent by performing 100 dives combined with a decent level of training.
Competent meaning they can perform a recreational dive safely, enjoyably, and comfortably. They have enough repetition under their BC to make tasks involved with diving semi-subconscious (you know, muscle memory combined with subconscious reflex).
cheers,
m