How long do you think it takes to train a Newbie till he doesn't need supervision and can solo?

6-9 months under proper supervision with a top notch training course in place. This way they get a variety of vehicles completed under a watchful eye. This will cutail incorrect installs and short cuts. Assuming the mentor or teacher knows correct procedures and approved company policies. Otherwise a newbie will do what he or she can get away with without knowing its incorrect.
Old dogs teaching old tricks ;-)

I was told along time ago,covering your tracks is what makes a good tech,(wow).I think at least 4 months depending on the person.Some are just better all around from the start than others.Start them slow(easy ones)at first and watch them.We train guys rather than hiring from other companys,that way you can mold them the way you want.Let them tackle the jobs also,while watching, they learn much faster.good luck!PAG training guy.