If I may chime in. It's better to get an engine with too much power rather than too little, provided there isn't a weight penality.

I have an OS 50SX in my Hobbico Superstar trainer. My instructor has said on a couple of occasions, "it's got soooo much power".

I bought the 50SX because I wanted an engine which would outlast my first couple of trainer planes.

It's common to see the 40LA being sold on eBay. In various ways the seller will say that they have moved onto engines with more power.

Good luck with your progress.

Bye, Ian