www.troybuiltmodels.com has a ton of stuff for giant scale and can most certainly get you going in the right direction. Some folks use the giant Seiko servo on the rudder, others use 3-4 servos ganged pull/pull. With a DA 150, 3w 150/157, they come out nose heavy, so lots of folks place 2-3 servos in the tail for the rudder on push/pull.