Wrong bit for the spiral dive effect - Adverse aileron roll will act in the
opposite direction to the roll, Left aileron up/right down = roll left, left aileron is in lower pressure air than the right so yaw
right so with secondary this effect of roll this opposes rolling into the turn.
Once in the bank the aircraft will tend to slip in towards the center of turn if back pressure is not maintained (look at the forces in a turn diagram), this will then give an aerodynamic turning force to the left - i.e. Yaw left, and this will develop into the spiral dive so it is
not the adverse aileron yaw that causes the spiral dive.
Going back to the origional question, spiral dives will occur in nearly all aircraft (there are some that have side areas fairly evenly distributed, but not really in a modern light aircraft) and yes, a large fin will tend to spiral dive a little quicker than a small fin - but generally both will do it.
Dutch roll is a seperate subject again, most light aircraft are not subject to it though it can happen. Dutch roll is a oscillatory condition which can be seen by the aircraft nose gently(normally) rotating about a point on the horizon. This tends to occur on airliners and is compensated for with yaw dampers.