A .46 2-Stroke won't overpower your trainer
I learned on a Hobbico Superstar ( which i believe is a bit smaller than the Lt) and I had a .51 2 stroke on it..
My opinion is start with the 2-stroke... The convert your plane to tailgragger and put in the 4 banger.. then buy a second airplane for your 2 stroke!.
I LOVE the bigger two strokes.. Owned 1 4 stroke.. Ran it a couple times and sold it!