RE: Boomerang Nano!!!
I balanced mine upright, on the wing just inside where it meets the booms. Just put alengthof narrow pinstripe tape spanwise along the recommended balance line, 273 mm forward of the wing trailing edge, and balance there. You can feel the pinstripe with your fingers and lift from there. I balance mine with a full airtrap/UAT and all batteries installed as they would be for flying. Had to add about 3 oz of lead ballast to a hollowed-out nose block and have been flying it there for about 3 seasons now with no problems. Good luck with yours.
Art ARRO