while that level of brillaince is beyond me
i will try to help you
plastic first needs to have grain added -all over and at the ends , preferably board by board to look distincitve and unique
a simple way to do this, is to use a modelers saw and draw the teeth lengthwise along planks-with a bit of a curve or bend so the lines arent dead straight
this can be done in varying depths, and of course you can add knot holes, with the tip of a modelers knife or appropriate sharp drill bit (neednt go all the way through the plastic
coarse sandpaper can also be used to create grain, as can single lines via the xacto knife
the next thing i have done -depending on the effect you like -ie new or weathered
is to paint the plastic a base color-very light grey works for me
for older wood, highlight using an almost dry brush with brown or red brown in streaks
black works too
allow to dry
or skip the above color dry brushing , and simply wash the grey primer with diluted india ink, this flows into the gooves youve created and adds detail -may look a bit too uniform but passable
so now you have raw wood or weathered grey wood
if you now desire to have worn-through paint, lightly dry brush over this, giving thought to where heavily weathered areas would be, such as on the bottom of walls, leading edges of overhangs etc-i like variation inf the color 'thickness' -start thin and add layers
i use broad shaders for this, thes help feather paint nicer than rounds
if you dont want painted wood
another material that can be used beautifully, is artist chalks-get sepia earth browns, rusts, even oranges and deep red browns and ochres
as well as black and a few steps of grey light to dark
scrape off the dust and brush on or rub in with your fingers-this too will reveal the grain detail and add interest by color layering
chalks are messy, work over a paper or the like,
and they must be sealed-and WHEN they are selaed-uisng a matte sealer from the art store-or even flat clear spray, you will find they almost disappear once sealed-so experiment, but i tend to put chalks on very heavily for this reason since the will be greatly reduced
i have used too, for bigger stuff, simple dry paint pigments in chalk dust form -colors like raw sienna, yellow ochre, burnt sienna, oxide red, these look great as newer wood -and you can blend them too
i put them on my fingers and rub into the plastic -it stays, and i brush off the excess and then seal-
it works really well and will give you a really nice look
but its all dependent on the grain and other scribed /cut details-
thats what i know
its time consuming and the eye does pick up little things, so care in creating plausible grain and variations will pay off -especailly board ends, no tjust the middles of planks
deeper lines too really show up and hold india ink wash (be certain to get india ink -a pure black-some blacks will dilute to blue-ish and this is a disaster -completely changes the look -also try to get as fine a ink particle as you can-to avoid little black pigment granules when it dries from dilution, you can also try, over completley dry paint, washing the surface, on the flat, with a soution of water with a drop of detergent to break surface tension-and then wash the diluted ink-but the surface must be flat or the wash will simply run off, if its flat you et crevice penetration and pooling that usually looks nice once dry)
btw when i dilute ink, i use meths, not water. To decrease drying time, i use 91% meths
70% works and what it can do is give you drying lines, like a receding pond with old water levels apparent-also interesting, but i far prefer 91% -i never use 70% on woods or cardboard or paper as they will become soaked and soft and warp
make sure each layer (of paint, chalk, sealer, etc, is fully dry before you add-or youll get a sloppy mess of colors -
paint can stay soft and the meths can furhter soften it if not fully cured and dry- soft paint may get to be messy too if rubbing in pgments
cheers!
hope it helps