*thinks* Both of them coming from the same joint capsule is just so...difficult. And wouldn't give him as much of a benefit.

I'm just remembering this science program where they tried to show what animals could evolve into and there was this high flying four winged blue bird. The second pair of wings were actually it's feet. (That's right, it flew spread eagle.)

If the second pair was offset from his main wings, tilting backwards, that might help. Or, ooh! He could use his second pair of wings to create an airfoil with his first pair. No flapping=silent running?

*trying to figure out options and possibilities and oh god I want to sleeeep*

Yeah, metal wings. Or cybernetic wings. I had a brief flash of Panzar Dragoon Orta.

You could web some of his spines along his side for more maneuverability? If they are muscular...