Barry,

The pitch trim tab on my IV-P can move upward (nose down) 14°, and downward
deflection (nose up) 24°.  You can see that I biased the deflection from
neutral to limit the amount of nose down force that I'd have to overcome in
the case of a trim switch run-away in that direction.

The 14° may, in its self, be too much in that I've never come close to that
position.  My normal fast cruise (195 kts indicated) will have the indicator
at the third dot.  In a descent I've seen the indicator at the second dot.
This gives me a descending speed of about 225 kts indicated.

Quite frankly, I've never paid attention to the indicator to see what
position its at when trimmed for landing.  I don't think that I've ever come
close to the 24° maximum for nose up.  I'll have to set up a slow speed
cruise (the next time I do a gear down manually check) and look at the
indicator.  I'll do this sometime next week and let you know.

Hope this helps.

Hal