Go with the LT .40 and an OS FX .46. Don't use a 4-stroke for your first engine. It's hard to tune in and takes awhile to break in to obtain a reliable idle. When it does though.......what a sweet sounding engine.
Two strokes are ideal for a beginner, as it's easy to set the idle and tune. The engine is transferable to your low wing second plane also.

Cheers.