Artisan, I used a 9/4 on the St. 23 also. I flew mine with ailerons and just had a ball. The St. 23 was tight fit, so I imagine the OS .35 was even tighter. I did see a lot of .35 powered Falcons fly well. I built mine light and learned that a light airplane always flies better. Tose old ST carbs were a joy to run for me- so easy to set up. You just couldn't get them to run right with a closed muffler with that sub- induction porting, though. But they would last forever. Who can forget the sound of a ST Bluehead when you throttled back and it made that " ring a ding,ding" noise?
Frank