I just can't decide in my mind if spinning a new to me, "hot" airplane on 1st flight is pure balls or really dumb
That is understandable by todays standards which are all about regulatory compliance. It was different then. Spinning was normal procedure and nothing to be scared of. Even at civilian flying schools it was common to practice solo spinning in the training area on your first area solo. For RAAF trainee pilots spinning in Tiger Moths and Wirraways was all part of learning to fly. In other words no big deal. Spinning a Mustang on your first flight was all part of briefed upper airwork as was aerobatics.