Getting the tail dialed in perfectly can be done...but takes time. Not sure what you've got for gyro or transmitter, but if possible (while in a hover) you should be able to switch the gyro from HH mode to normal with your TX and see if the tail rotor needs more/less pitch. If thats not possible then I'd find a really smooth surface, throttle up (HH off) until your light on the skids and see which way needs adjusting.

Few guys I fly with (myself included) can turn our GY401's from HH to normal while in a hover and have the tail sit completely still. No trim or sub-trim needed.