I will say that the answer to your problem is yes, you'll need a lot of left aileron or rudder trim to get the plane to liftoff and fly straight and level. I have worked with several guys flying nexstars and they ALL drop the right wing on takeoff. We had to add a ton of left ailerons to everyone for straight and level flight and they still fly to the right on liftoff. We were just discussing this exact problem and comparing 2 of them at the field the other day. I dont know what the problem is but its definitely there. With all of the dihedral in the wings, rudder behaves a lot like ailerons. Try trimming it out with Rudder and leave the ailerons level and see if that helps any. Once you get the settings corrected with trim, mark it and readjust the throws to that position so that you can get the trims back to center so you have trim again.