[WESHOOT2]

Screw SAAMI; their data/limits are lowest common denominator.

Next, I like 'safe' as much as anyone (repeat after me: "liability insurance").

And even more important is the "...but not always..." philosophy REQUIRED to remain safe, because all guns are always different.

Modern guns in good condition can be loaded safely past most of the SAAMI specs, BUT NOT ALWAYS.
European standards, while higher, are not absolute, either.

Common sense and the black art of reading pressure signs are mandatory as you push loads ever faster, and a good understanding of risk is helpful (so you're not pissed when your gun grunts).

Mapping the powder/velocity curve seems very helpful (chrono required), and measuring cases can add to that, but at some point one must admit to oneself that one is guessing.

And how can I know how YOUR gun will perform?
Will my "Gray Area" load be safe in YOUR gun?
Is YOUR gun in safe mechanical condition?
Does YOUR gun have a tight chamber/close lands/undersized bore/etc.?
Will YOUR GUN be fired in extreme hot/cold temperatures?

So many variables, and I'm with Art and the others: be safe, go slow, observe carefully.
At some point it's 'enough'.