LA40 is fine.

This is not a suggestion, but... in Real Flight, the PT-40 flies fine with a Norvel .061. It even climbs In the real world I don't think it would get off the ground, except perhaps off a really smooth paved surface. It would probably stay in the air if one is careful. The Lift/Drag of a model like it is, I'll guess, around 10-15. If it weighs in at 60 ounces, then at best L/D speed you only need 60/10 = 6 oz of thrust to overcome drag and keep flying.

Maynard Hill's 11 lb model flew across the Atlantic with an engine running at about .2 HP. Which is about 1/4 what an LA-40 produces at full throttle - and that, typically flying a model that weighs 1/2 as much.