What are the maximum possible stabilizer and elevator deflections for the A320?
As per the A320 flight manual (§127.20 p3), the maximum permitted total pitch alteration in normal law depends upon speed, aircraft mass, CoG, and other factors:

Pitch Attitude Limitation:
Pitch attitude is limited to:

30º nose up in conf 0 to 3 (progressively reduced to 25º at low
speed)
25º nose up in conf FULL (progressively reduced to 20º at low speed)
15º nose down (indicated by green &quot;=&quot; symbols on the PFD's pitch scale)

The flight director bars disappear from the PFD when the pitch angle exceeds 25º up or 13º down. They return to the display when the pitch angle returns to the region 22º up to 10º down.

Likewise, the maximum physical elevator deflection is 30º nose up and 17º nose down. The maximum trimmable horizontal stabiliser deflection is separately 13.5º nose up to 4º nose down, but the plane will always fly within the total pitch limits specified above.
Good luck with your project!