Here are the throws I ended up with on my predator with an O.S. .46fx.

Ailerons and Elevators

Low Rate 1/4" up and down
High Rate 3/8" up and down

I take off and fly on low rates, and only use high rates to land.

You may want to go with slightly more aileron throw for the test flight. Some of the wings aren't exactly straight and you may need the added throw to keep it level.

As to a motor mount, you can get backplate mounts from a variety of sources. For sportflying a Hayes mount works fine, just mount the engine as close to the firewall as possible.