I think your on the right track to increase the wing incidence doing so one mm at a time. If it was very sensitive on elevator, then moving the CG forward slightly will reduce that. That you were able to recover and land the plane, seems however to indicate that the CG was not grossly aft.

Engine up thrust is a rare thing. Down thrust is common on asymmetrical foils to counter the increasing lift as more power is applied. Given that your plane is increasingly trimming down with more power, it seems almost certain that it has negative wing incidence.