Before attempting to adjust the elevator trim, double check for any misalignment issues. Make sure the wing is not twisted and is aligned correctly with respect to the stabilizer. Make sure the model balances at the point recommended by the manufacturer. It is better to be a little nose heavy. You might have to shift the battery position or add weight to get the right balance. Also, a little downthrust might be needed to prevent excessive climbing under power. If your ship is aligned and well balanced, you should not need more than a few clicks of up elevator trim to achieve level flight at moderate power settings.