While I don't know that motor personally, I have messed with a few different 25 cc's. I wouldn't expect to 3D a typical weedie 25-26cc conversion on a magneto.
Look for a plane that a g23 will fly. Your idea on the cub is probably dead on.. I have found a plane with the upper 800 square inchs and up will fly, I have seen others mention 900 square inchs, that definately gives you a little more wiggle room. The CMP hellcat is a good choice to fly nice and hide the motor decent, ugly stick (GP 60-90 with mods) But once again the 120 size cub would putt around nicely...