I am using some arms that came with a 3D hobbyshop 47" plane. They were made to screw to the existing arms for an HS 65 servo. They worked just fine on the Power HD mini's I used. Here is a link to the servo arms.
http://www.3dhobbyshop.com/detail.aspx?ID=2193
I only had 3 but I made two more out of some lite ply. Tom I sure enjoyed the visit with you and your wife last Saturday. Did your pool thaw out yet? Is there any video of this plane on You Tube or somewhere else? I would like to see it fly.
Lee Mitchell