The G-26 weighs around 53 oz, so the plane will be way nose heavy. I had an OS 1.20 III pumper on mine. That engine weighs around 35 oz, and I still had to move the Rx battery pack way back to get the plane to balance.
I'm going to try the Roto 25 gasser next:
It's a compact, smooth running, 25cc (1.50 ci) engine that's pretty much the same size as a Saito 150 and swings the same prop at the same rpm. [link=http://www.rcshowcase.com/html/engines/roto25.html]Click here[/link] for more info.