You should also realize that there is no such thing as a generic scale propeller. Each WWI propeller was designed with one specific engine in mind. Thus what was scale on one aircraft would not be scale on another. In general, the more curvy and "asymmetrical" prop designs went with early engines with limited horsepower. As engines became more powerful, propeller designs moved more toward the shape of a Zinger prop. For example, the shape of a Zinger looks pretty scale on a Fokker DVII (though it would still be too small for scale diameter and with too little pitch). That same Zinger would look decidedly un-scale on an Fokker EIII.