If it were me I put him the wing and give him free reign to float and get involved as often as possible, tell him to ruck it out as often and hard as May/To'o, let him roam and get him running inside lines off his wing, give him a chance to contest kicks and go for intercepts as often as he likes and maybe he gets you a return on your money.
He's not much of a fullback, but you don't have to be to look good there in a decent side against rabble and make the world think otherwise, so it may work out for him anyway.