I will throw this out there: I like to have my students balance their trainers a little nose heavy, 5-8 degrees down when held at balance point. This helps in making the plane more stable in the air and makes the glide path on landings a little easier to manage. The planes tend to float less when landing. Just something I picked up years ago in RCM. I think problem here is the ST engine. I quit using them when the engine blocks are machined from a block of aluminum and that ugly heavy muffler went on. It is one of the heaviest engines out there.