RE: Pheonix Extra 330S 60-90 Size
What does your elevator trim look like for neutral, hands-off flight?
If you must carry down trim for straight-and-level flight, could be that you are essentially flying with wash-in in the wings and need to reduce wing incidence by raising the trailing edges of the wings by 1/8".
Earlier in the thread I posted some photos and description of how to do this.