Mine also does carry left aileron trim. Did you check the incidence of the wing panels?
Mine has different incidences for wing panels. Haven't tried adding plywood rings for incidences yet.
Mine also flys with tail down, and up elevator trim. A little tail heavy CG, but noticible.

When I worked on the one for my friend, we went for dual elevator servos. Checked the horizontal stab incidence also.
If you push the horizontal stab all the way forward, it will have positive stab incidence of more than 0.5 degrees.
We pulled the H-stab backward to set the incidence to 0. Much better than mine.
It also has left aileron trim.
Checked the wing panel incidence. it was about 0.3 degrees off.

Weight difference doesn't matter much on this plane unless it is a lot. Mine has heavier left wing panel.
Plane will dvelop slop in the alignment hole in a few months. My left wing moves about 1/16" on trailing edge.
Since I started flying 2m, I haven't flown it much. I am trying to set it up again to fly slower and similar to my Abbra.