I have a Saito 56 on mine and love the combination. I think the OS may be a bit heavy for this airframe. The trade off of power may not be worth it. The Saito 72 would be a better choice if you need 3D power. Prop clearance may be an issue.

Difficult to believe you can get that TT .46 to perform very well with a 11X3 prop though. Have you tried a bigger pitch like a 11X5? Or 12.25X3.75?