Im in two minds about this whole washer spacing set up, as mentioned in that ED38 thread you'd be putting extra unnecessary stresses on the hub bolts due to creating a space between the stub axle and rear beam. Admittedly if only using a small washer on one of the bolts then i doubt it would be significant increase but im still unsure as to whether id be comfortable with knowing something as important as the strength of my rear suspension had been jeopardised.
I reckon if camber is needed then shims is definitely the way to go as you'd alleviate the stresses over a larger contact surface rather than simply across the adjoining bolts.