RE: 4 stroke .81 size Os or Saito?
"Snot Slingers" - ROTFL!
I'm not having any problems with that.
I'm running 5% Cool Power on mine and IMHO I have them tuned up pretty well.
I have a Saito 1.00 on an old Funtana S90.
I see a lot of complaints about this combo not producing a lot of power, ( a lot of people went with the 1.25 instead ) but with a "W" prop mine pulls stumps!
I wonder if it's because I'm flying at a lowly 230' altitude?
There's no excess snot to speak of, but I do have the exhaust angled down and away from the plane.