Torres - RDB was ex-TAA, and a converted -100.
The ex-Golden West aircraft you are thinking of was P2-RDA (originally P2-GKR). RDB, like all the other ex-TAA machines (RDC, RDD, RDE, RDH), had a different electrical system from the standard de Havilland issue. RDA and RDF were the 2 lightest machines, and (theoretically) could carry the largest payloads.
"Shags" and his team in POM were uncertain about the payload limits, and instituted a flight test program (lasting several years) to establish which aircraft could carry the heaviest load.
