I came to the conclusion rather quickly that 6x4 would be a simpler solution, or at least forget the lift axle (for now, might revisit it later).
Getting rather excited to see it drive so the printer has been running almost nonstop for the last 48hrs and this is what I came up with
Don't know if there is a name for this kind of setup, walking leaf suspension thingy.
Haven't given up on making leaf springs but while still in testing phase it's easier to just print a pair.
Also put a little paint on a couple of parts, will need a few more coats and wet sanding to get rid of all the lines and imperfections.
The colour isn't exactly what I wanted but still pretty close. It's a standard rattle can colour and only 5min away so I'm rolling with it...