RE: Omega or Cool Power for my Saito?
Nothing wrong with all synthetic as long as you do not make a lean run. Not being perfect, I add Castor to Morgan's Cool Power (or vice versa) or use Omega. Recent article in Model Airplane News, says uses some Castor, less in four strokes more in ABC two strokes, but use some Castor!
Use if only for a rust preventer, but use it. Bigger engines need less oil in the mixture but again some Castor is recommended.
And finally, it is your engine, do what you want.
Cheers,
Chip