Here it is the final batch of mercs. I painted these ones exclusively giving them a base colour coat and then a wash with no lights at all except for the soil of the base and the metallic shine in the guns.
They would be better with some lights on berets and helmets as well as on flesh, but I wanted them just after the wash and varnish to compare them with highlighted ones.
I think they turned out quite good but I fell I can still improve results as I was trying right proportions in the mixture. Rougly, I used 3/5 parts of Mercadona floor wax and 2/5 of acrylic Betumen of Judea. I also used lighter colours on the figures to prevent too much darkening from the wash.
I used to wash directly with Mercadona wax and ink, but the mixture got to watery and run so fast on the figure that some details weren't properly covered by the wash. However, now the Betumen of Judea is so thick that allows the wash to work similarly to the oil versions, and it gets a better coverage and result.
I am still struggling with the right proportion and you can see below the difference in the top left and right figures with the two ones in the middle who are lighter or cleaner.
This picture is to show you the difference between wash and no lights at all (left) and wash and lights (right). The details in the figure are so thin and small that I cannot highlight them properly so they get better without lights IMHO, and get done in half the time! Plus the miniature gets a hard protective cover from the wax, so it is a win win situation.
If you observe the webbing in both figures below, you will understand what I am saying.
Here is another example.
This technique is fast and it gets good results, but I suspect it works better for WWII than for Fantasy or Sci-Fi if you want brighter colours.