I tune my Saito's by ear all the time. If your instructor is comfortable with a four stroke, there is nothing wrong with putting one in a trainer. I have a Telemaster 40 with a Saito 65 on it and I buddy cord "newbies" all the time. If you think you want to use four strokes in your airplanes and the higher cost is not a problem, I say go for it. There are plenty of people in your club that can help you learn to tune you four stroke.