you're missing my point i think, and i'm a little confused as to what you're trying to ask?
if you're running 3 degrees negative camber of course you're going to suffer from tyre wear to the inner edges, and if you rotate them you'll end up with worn shoulders on both sides with more tread in the middle - which is the norm.
if you want your tyres to wear dead even, then run zero static camber (which i wouldn't recommend) but even still they won't wear dead even due to independent suspension and dynamic camber (camber changes under load).
my original point is, if you want to get the most out of your tyres with a little negative camber, run a couple of degrees toe out
i hope that's helped?