For what it is worth, the few aircraft I have seen in museums with painted wing surfaces (albeit reproduced PC10) have an effect where the fabric over the ribs looks more glossy than the fabric between the ribs, but with more or less even colour.
If it was me, I would use one of the colours (perhaps matt - always looks less black to me due to the relative roughness of the matt effect) as a base coat, then overspray with a satin effect black. Sand back between the rib areas with fine material - I use micromesh - to reveal some of the underlying colour and to give a slightly non-uniform colour. Leave the ribs as they are, to remain slightly glossier which gives a darker appearance. If you are satisfied, leave as it is. You can further affect the inter-rib material with weathering powder/pastels if required.
If you want a sharper edge between the ribs and the fabric in between, use thin strips of tape to mask the ribs before sanding and pastels, or spray the glossier paint first, mask the ribs then overpaint with matt colour and sand back as before. The effects can be toned down further with varnishes or washes as you prefer.
I would love to see the pics of this build Bob. Here's some pics from my late Fee build, but have a look at Przemol's build (and others) on here too.
Here's a before and after pic (or after and before looking left to right!)

Wings painted:

Finished:
