Ed,

I think the first thing I would do is verifiy the CG to be nuetral or slightly nose heavy. Take off and pull a 45 degree inverted climb at about 1/2 throttle. Let go of the sticks and see what the nose does. If it stays right there your CG is neutral, if the nose starts to point up you are tail heavy and if it starts to drop you are nose heavy. The fater it moves in either direction indicates just how heavy you are in that direction. Try to get it to either completely neutral or very slight nose heavy (espeically nose slightly nose heavy with a full tank)

Onjce you have that if it still takes a bit of down trim in straight and level then I would start off by adding one degree of down thrust.

The confusing this is the pull to the canopy on anything other than a vertical downline. That could indicate a wing incidence problem. I would find a trimming chart, startt at the top of it and work your way down. Figure around 20+ flights to get a plane trimmed correctly