Acording to many of the best knifemakers in the world, the lockup in your first pic is ideal. You want it to engauge as little as possible and still be secure. This allows the lock to last longer in the face of wear.
So, give it a spinewack test. If it passes, then the lock is secure.
Whether the lock is like in the first pic, or second pic, doesn't really make much difference in security. If the lock slips, it slips. Being over futher only adds a tiny bit of friction to help prevent slippage.
As you use the knife, the lock will move over.
Only put lube on the lock and tang if it is too hard to unlock. Putting lube on a lock that you are worried about being secure is not a good idea. If it isn't secure, lube will hurt, not help. It will not increase break-in, it will decrease it, and it will increase the chance of failure.
But again, just give it a spine wack. That will tell you if it is over far enough or not.
Some of the other best knifemakers think a lock with more contact is better. I don't know which is right (probably both), but I think they are both means to the same ends. And that is why I say test it. If it is secure, it is secure. The different theories about which tang/lock contact is best are just theories. Secure is secure and both schools of thought seem to be able to produce secure locks. Knifemakers of both schools have produced strong locks and become world renowned.
