Lifting the airplane by the spinner is not the correct way to check lateral balance, as the crankshaft centerline isn't in line with the fuselage.

You need to find a spot on top of the fuse that is dead center, and lift there.

Another way to check right/left thrust is to pull into a hover and see how much rudder input you're having to give. Mine always went left(I was constantly having to input moderate right rudder to keep it pointed up), so I added right thrust to the engine till it didn't want to go the same way every time.