I have a rule of thumb.
If the model weight (finished) is the same in “ounces” or less than your “cc” of engine displacement then you should have a competitive model.
e.g. A 40 oz model with a .40 sized engine = Competitive.
THIS DOESN’T APPLY TO 1/2A SIZED MODELS. A thru D ships only.
I had a Satellite 1000 that weighed 34 oz and was powered with a K&B side port .40. This model flew like it was a rocket on rails. When the model DT and came back to mother earth the landing gear skids didn’t even bend.
Just my 2 cents worth.
Again…a very light model.