ok i did some preliminary testing and i made a temporary production recipe
what your gonna need is a Pipette (for dosage), paint thinner, transparent gloss (revell or humbrol,...), steel metallic paint (revell 91, or for alternative brand, check paintcharts), toothpicks (or piece of leftover sprue, for mixing) and an empty paintjar, pantrydish or something else to mix the paint in.
take your mixingdish (or jar, pantrydish,...) and pour in, using the marked pipette:
-3.5ml Clear paint (preferably gloss)
-1 ml steel metallic paint
-4ml thinner
then mix it all toghther, you should get this result (can look bubbly)
before painting it on your intended model, test it on an older model from the scrapyard first. if the coat is not clear enough, you can always ad more thinner, if the mixure it to liquid, you can ad a bit more transparent paint.
the test with this mixture is shown on these pics (marked in red squares)
close up
tail surface
the recipe i noted is for quite a large dosage, so if you paint is satisfactory, anf you have some left over, you can always put in a tin or jar in case you need it again in the future.