Hi Dave,
I recently bought Phoenix Sonic ARF. It is a .25-.30 low wing airframe. I think it will accommodate the engine properly.
Btw do you start your 40 FSR engine manually or with an electric starter? I found that my 40 FP easily starts with an electric starter but quite stubborn to start by-hand. Usually I start my 2-stroke glow engines without electric starter, so I am puzzled a little.