Concur with that. My "ROT" ("Rule of Thumb") is to figure what engine I would use were I going to fly the model with a single engine, and then use two engines of approximately 1/3 that displacement. In other words, if a .60 would fly the airframe well, then two .20s would be about right; if a single .90 would fly it, then two .29s would work instead. If a .40 would work by itself, then 2 x .09s will suffice. More twins have died due to being overpowered and overweight than any other cause. Jim