I have flown every trainer available as club instructor including some you may never have heard of. I learned on a "White Cloud" that was modified from a free flight model. At that time some pilots were still flying reed systems and the magazines had articles on how to build your RADIO over several issues. My point is I've been at this a while.

My favorite trainer from your list is the LT-40. After flying one for a student I bought one myself to use as a club trainer. An OS 40 LA will fly the plane fine. A better engine will make it really perform. I have an Irvine 53 in mine because it also has a set of floats to fly off the pond. I doubt if it will need that much engine however. Rudder and fin are large and effective. This plane was originally a 3 channel (no ailerons). The students progress much quicker with this plane than any other. I had one student that seemed never to "get it" as far as flying was concerned. He bought an LT-40 (ditched the coroplast plane) and has learned to fly. This aircraft is capable of really learning. I have flown rolling circles with mine.

Should you learn to build? In my opinion yes but you don't need to build your trainer. It would also cost more to build. Learn to fly and start building that second plane with the goal of progressing. (A P-51 is NOT a good second plane).

If you have any choice learn to fly with an instructor.

EXCAP232