os 1.20 would probably work well, I have old OS 1.08 & its perfect,just the right amount of power & weight. If the 1.20 weighs near the same, I would go for it.(I've also had a Moki 1.35 in a .60 Do,if it fit,the 1.20 surely will). If you want to 3-D,70-80 4-strk is not enough IMO. With snow in the forcast we still went out flying on Sunday,(Jan 21)it didnt start untill later in the day and the winds were light and the temp was around 37. Only a couple of "die hards" there but it was good enough for huckin down on the deck,I keep bringing the Do when its bad weather,guess I'm saving my pretty planes for later. I'm bringing the rolling harriers down to 10ft now,still dont like any lower. When I really screw up, the plane ends up heading straight down,havent done that lately but that's why I'm taking my time getting down low in that maneuver. Other than a few hovering tail touches,nothing new happened. A new member has a Giant Do,this should be interesting.