Take two on the camel's woodwork.
I took the advice of ww1aircraftmodels forum denizen Ryan, and passed on the woodgrain effects. Instead I sprayed some Tamiya dark yellow mixed with a few drops of orange, and then applied a coat of Vallejo clear orange. Obviously I haven't painted most of the details yet, but I'm much happier with how these look now. Thanks, Ryan!
For the blackened metal brackets (japaned or galvanized?) I'll use a mix of Vallejo black and Ammo gunmetal, like I did for the rudder bar details seen below. The engine still looks meh, but it's good enough for now.