most cars these days will always generate more negative camber in the rear than the front when at the same even ride height front and rear - and the GVR-4 is amongst this list. Even at factory height the E39A has about -1.5 to -2.0 deg of camber in the rear while the front has -0.5 to -1.0 deg. That's just the nature of having macpherson struts in the front and wishbones/multi-link in the rear. The 7G and 8G Galants are even worse, my last 7G was lowered about an inch and ended up having -3.5 deg in the rear while the fronts were barely -2.0. My 4G Galant coupe with macpherson strut IRS in the rear also generates more negative camber in the rear than the front. Having increased negative camber in the rear helps with rear end stability in cornering and perhaps would induce quite neutral under-steering handling, however that would only work up until a certain degree where anything excessive would actually cause a severe lack of grip as the contact patch decreases because the body roll can't match the extreme angle.
I would agree mostly with the above, except I would have perhaps -2.0deg up front and -2.5deg in the rear, and have a little bit of toe out on the front to aid with cornering. Having a stiffer rear sway bar would help with reducing understeer a bit.