cheers people, and as for weathering....that's what all the devlan mud ink on the model is for. and the colours are sort of stippled on and are a bit splotchy and uneven. It's probably not visible on my phone camera with flash but it's how I've done all my ork vehicles and it works. This one looks a bit cleaner than the others perhaps.
it's also really quite hard to do scorches and burns when the primary method (devlan mud) is all over the plane lol
but yeah, cheers for the feedback