Man that looks the biz!! Great work Dan. I agree with Keith about the dust/dirt. The opposite should work to give a dusty appearance - a very light dusting of sand, or light grey, when the gloss coat is on. That way, it can be removed easier if it looks wrong. When it's matt coated, maybe a dusting here and there with mid-grey pastels. Again, they can be removed if wrong.
For the canopy frame, there are two ways. One, paint some tape, such as Tamiya masking tape, by laying it down on glass or another smooth surface, then cut strips and apply as frame work. Coat these in Future to seal them, then, when dry, go over them carefully with matt coat.
The second method is better, but a bit fiddly.
Mask, then paint the interior colour first. When dry, brush paint two coats of the exterior colour. If you can, you can then follow the line of the internal paintwork, and paint this too in the appropriate colour. If the canopy is going to be open, you only need to do this on the part that shows, which will be easier to access.
When the tape is removed, it should leave a slight ridge of paint, which will give the scale effect of the frame.