More info needed... flybarred, flybarless?
if it is flybarless there should be ZERO TRIM... why? the flybarless unit sees any command given from the remote control in your hands as a control command.... for example you setup fly your heli and add trim, now the flybarless unit sees that trim as a control input rather than a "trim".....
To properly trim the flybarless unit you will have to look at the manual for the ar7200 bx.. assuming it is a ar7200bx. (
http://www.bladehelis.com/ProdInfo/Files/SPMAR7200BX-Manual_EN.pdf) and go to menu A in the parameter menus pg. 23. and adjust the trim there...
If your machine is flybarred I would look to ensure the swash is level. If it is level (perpendicular to main shaft) then double check the CG and all the links above the swash. If it is not level then there is your problem.
My guess is still that your heli's CG is still not correct and you are compensating using trim...
put everything on heli including canopy and battery as if you were about to fly it... just want to make sure of which method you are using... use the method in this video at 2:00,
https://www.youtube.com/watch?v=EBGd4NVl-VA
anyways try that and let me know