Thanks to all for the great comments (all greatly appreciated!) - and I'll try and answer a couple of questions...
PrzemoL - yes, I will add all the cowlings to this and button up the engine since I like the final model to look as flight-worthy as possible. This is one of the most awkward looking aircraft, but in an interesting way. If you know what I mean :-)
The grey colour I've used for the cowlings is my own mixture of Tamiya paints which I made a batch for when I did the F2b this past year. I can't even remember what I mixed up, but it will look entirely different after I've weathered it. I've also bought some of those photo-etched "splatter masks" to experiment with making the cowlings look quite mucked-up.
Lance - you're right - I painted those engine bearers very carefully using that microscope I was telling you about. Glad you approve! Finally got to use that circle cutter I bought in Calgary last June and painted the roundels on the lower wing. The ones on the top wing may be tricky with that thin white outline though....
Cheers,
Gary