John (@johnb), I have been thinning the paint 3:2 paint:thinner. I don't have the flow improver so I might go get some. I still find that the green is more translucent than the other colours.
George (@gblair), I used the dark grey to mid-shade (?) the light brown and then go over the light brown again.
I have done this in the past - paint the camo colour, pre-shade and then go lightly again with the camo colour.
I tried to lightly sand the brown wing tip where there was a little build-up of the paint but ended up scratching the paint off - evidently it doesn't like sanding. I repainted and the scratches are not too obvious - hopefully they will disappear further under a clear coat. Maybe I should use a primer with these paints in future.
3 attached images. Click to enlarge.