Classy Plague Marine

This plague marine here is probably one of my favourite models, I believe he's from the 8th edition box set. I got him in like 2018 in the store before I really knew what Warhammer actually was because me and a friend went in there, he spent a good few years on my shelf collecting dust until a few weeks ago when I decided I'd strip all the old paint off and do him some justice. I had to replace the head as the old one has a spike on it that had snapped. Id love some advice on highlights because I don't really understand them P.S said "classy" PM because he's not smothered in Agrax Earthshade 😂