Hi Jamie,
when I did my project I really juggled between roller painting & spraying...
I ended up spraying which in my opinion went ok... a little orange peely but only up close.
I used paintman paints who has a huge range of colours, it’s mostly synthetic enamel & really goes on well.
I roller painted a few items such as the load bed & other bits n bobs & it went well, no brush marks or witnesses of the roller.
what I’m getting at is you can get a decent finish with either spraying or rollering it’s just time, patience & lots of prep work.
Ben