A quick and easy way to get Cultist up to tabletop quality.
Paint skin with   Darkoath Flesh  
Paint cloak with   Volupus Pink  
Paint pants with   Gryph-charger Grey  
Painted all of the wrapped bandages/fabric, interior shoulder guard on champion and the horns on the champion with   Skeleton Horde  
Paint all straps and holsters with   Snakebite Leather  
Painted outline of left shoulder guard on cultist champion   Brass  shaded with   Agrax Earthshade  
Paint boots and weapons with   Black Templar  
Paint armour plates, helmets, weapon accents and 8 point star with   Leadbelcher  then shade with   Nuln Oil  
Paint hair on unit champion with   Nazdreg Yellow  
Paint hair on cultist with heavy stubber with   Gore-grunta Fur