RE: Great Planes 1/4 scale Gene Soucy Extra 300S Review Now posted
Your Saito 1.50 would do well in many planes the same general size as the GP Extra, as long as it's a newer, LIGHTER design. The Extra 300s was just old and heavy, IMO. I ran a Moki 1.80 in mine and was left craving more.
Look for something in a 60 to 70 inch Edge 540 that is built light. Your 1.50 would likely do very well in the new Funtana 125. It's quite a looker too.