Arbiter repaint -Needing help -

So I repainted the arbiter figure with an acrylic silver with a black wash. Sense Google has 0 idea of what to do, or how to do it. I did not put a primer, which from what I hear.. many dont...

So I'm wondering how long I should leave the figure for (estimation) , cause I dont want to scratch up the paint and I want it to be permanent.
The paint used was a fast drying acrylic by the name of decocolor. Thanks