The Mercury has probably reached its final iteration. I rummaged in the parts box and found a higher KV version of the same motor. I combined this with a 6x4 propeller and about 5 degrees of down thrust. The previous prop had been a 8x4.5 slow flier prop. This mellowed the handling and allowed the good free flight traits to come through. It still cruises around nicely at a little less than half throttle