Here are a pair of the Dapol B4 that I have weathered, all the usual methods used, plus one extra – I thought the plastic body was a bit shiny so I coated them with a 50-50 coating of mixed Satin and Matt Varnish before weathering. I have weathered one Loco ‘light to medium’ and the other ‘medium to heavy’. See the difference with the photo of them side by side.