Thanks Nigel, Andy, Roel, and Rowan !
Roel - I mix enamels with a touch of black oil paint, and thin it with Model Master airbrush thinner. I apply it to the panel lines after the model has been glosscoated with Future. After the wash has dried, I remove the excess with a #000 brush that has been moistened (not wet) with thinner. I clean the excess from both sides of every panel line, and around each rivet. It's time-consuming, and you need to experiment first before trying it on a build. Too much thinner used to remove the excess can damage the finish. For this reason, many modelers use acrylics for a wash.
Rowan - the engine area was going to be masked for quite a while. Painting, glosscoating, washes, and Dullcote. This way, the masks are only over paint for a minimal time. If you look closely at the right tail just below the rudder, you can see where some of the wash leaked under the mask. That would have been a mess to clean if the Alcad had already been painted.
Thanks again !