I agree on the 120. Saito 120 on mine gives very scale performance. I get comments on how it looks and moves in the air every time I fly it. Running the Saito inverted with no onboard glow or pumps and its running great. Starts super easy as well and with around 25 flights, not a single dead-stick. So where onbard glow will help, it isn't absolutely required. From what I understand, proper tank placement is crucial especially without pump/regulator.

Have fun, the Ryan is a gorgeous aircraft.