I no longer have the benefit of my plane or plan since I sold them off a year or two ago. However, I do recall that the setup appeared a bit unusual. The engine was set with negaive thrust, the stab was set at negative incidence and as I recall, as it looks in the manual, the wing was negative as well. Mind you. I could be wrong. Sometimes our memories tell us one thing with 100% conviction when the reality is entirely different. Howeer, it sure looks negative in the instruction manual.
Have a look It's quite obvious that everything is negative.
A check of the plans will verify everything.
There is nothing wrong with the negatives.
It is just a matter of what reference line is in use.
Imagine that the main wings incidence is plus 2 degrees and the stab is zero degrees to the reference line.
Now select a reference line which is 4 degrees from the initial line with the front of the line upward.
Now the main wings incidence is minus 2 degrees and the stab is minus 4 degrees but nothing has changed else than the selection of the reference line.
Nothing has changed with the model.
Whenever a drawing shows an incidence angle it has to be obvious what is the reference line.
Most drawings have the reference line parrallel to the base of the drawing. We might say the rectangular lines within which the drawing is done.
Note that the distance of the reference line from the items, wings or stab does not change the angles.