Thanks for the additional replies!
My instructors have been setting the trim at about 1/2 throttle. This is the setting I have been doing most of my flying. But, I have seen w/o enough power, and a stiff headwind, my trainer will balloon up and stall....(Not good, makes for some anxious moments! )
Seems to be some good points to doing full, 1/2 or trim as needed perspectives. I'm sure I'll form my opinion based on these inputs, as well as my future experiences.
Bob