Hi, look to see if the springplate is touching the torsion bar cover at the top of the hole where the torsion bar comes through- new inner and outer torsion bar bushes will fix that.
Also, the alignment of the rear hub carrier to the spring plate will have more of an effect on the rear wheel camber, than the ride hieght. Beetles, or any other ACVW for that matter, do not like being reversed up curbs, this can kink the springplate and give the result your seeing.
The amount of adjustment available is quite surprising, I'd be surprised If the error you are seeing cannot be dialed out. It appears not many Beetle bodies sit dead centre on their floorpans
I suspect one of my torsion bars (1979 Karmann Bug) has 'sagged' a little more on oneside too. I'm replacing them soon with bigger diameter parts from a 944. Not decided which yet.
Matt