Thanks for the input!

Tower Hobbies recommends a .50 to .60 size 4-stroke for this plane,
but I'm not sure what they base their recommendations on.
I'd sure like to error on the side of bigger because then I can transfer
the engine to a larger plane later, as Razor-RCU mentioned.

My concern is always putting TOO heavy an egine on the plane which
would make it unstable or the airframe not being able to handle it.
I definitely like realism and climbing power versus speed, and I don't
have to fly at full throttle.

I'm a newbie with matching engines to airframes so the advice is
much appreciated!