So, inspired by the forthcoming A War Transformed rules, I picked up a box of Wargames Atllantic's Great War Germans.
https://ultravanillasmurf.blogspot.com/2023/09/wargames-atlantic-great-war-germans.htmlAs a proof of concept, I have assembled and painted the first one.

I was guided by the article in the North Star magazine, adjusted to the paints I have in stock.
http://nstarmagazine.com/A_WAR_TRANSFORMED_1.htm
After an undercoat of Citadel Chaos Black spray, it was painted with Citadel Mechanicum Standard Grey. This was highlighted with a mix of Citadel Mechanicum Standard Grey and Army Painter Stone Golem.
The gloves and mask are Citadel Steel Legion Drab.
The rifle wood work, grenade handle and parts of the entrenching tool are Citadel Rhinox Hide.
The pouches, belt and boots are Citadel Dryad Bark.
The Bread Bag was Citadel Rakarth Flesh.
The helmet was first painted Citadel Zandri Dust, then patches of Citadel Rhinox Hide and Citadel Death World Forest were added.

Metal work (rifle, bayonet and grenade head) were painted Vallejo Black Grey then dry brushed with Army Painter Stone Golem.
The lens surrounds of the gas mask were given a re coat of Vallejo Black Grey, then the lenses were first filled with Humbrol Matt White then Citadel Warpstone Glow.
Everything was given a light dry brush with Citadel Terminatus Stone.
The mask, helmet, boots, gloves, bread bag and woodwork was given a wash of Citadel Agrax Earthshade.