Maybe I jumped ahead on this since it is a WIP, but it looks very good already, so I resteemed it and also shared it on twitter: https://twitter.com/visionaryartcom/status/1061368637100097537.
Metallic: I use metallics at times in my acrylic painting. You can achieve interesting effects by thin glazes with metallics. There is also pearlescent paint.
Are you on Artisteem yet?
Check it out: http://www.artisteem.com/
Here is their Discord channel: https://discord.gg/WPHVKYw