So the eccentrics are adjusted all the way in and you still have positive camber?
If that’s the case then shimming the lower ball joint to push the bottom of the spindle out would be your only option. But that would also suggest something is wrong with the chassis or the UCA.
Sounds like he’s all the way in on the eccentrics already, which would mean he’s got no way to add negative camber on the right side that’s +0.5.