hawk37,
You mentioned internet resources for AC and pressure distributions, and the contribution of the tail surface to stability.
Perhaps you could look at
this site which describes the function of a tailplane with respect to longitudinal dihedral.
I have found longitudinal dihedral (or decalage) to be much more helpful than the concept of an AC of an aerofoil, in understanding longitudinal dihedral in a practical (as opposed to theoretical or design-orientated) sense. What I mean is, knowing the AC of a wing does not help me to visualise different loading / AoA scenarios - but understanding longitudinal stability does.
Two references that may help you, both of which are more readable and less mathematical than the Aerodynamics for Naval Aviators text, are:
Aircraft Flight 2nd Ed 1995, Barnard & Philpott, and
Principles of Flight 10th Ed 1998?, AC Kermode.
Milt
Natural longitudinal stability for an aircraft is achieved by having the Centre of Pressure behind the CG which has to be between forward and aft limits..
I think this may not always be true. In some circumstances the CG may be at or slightly behind the CP, the aircraft
as a whole still having slightly positive static longitudinal stability. Most civil aircraft are quite strongly longitudinally stable, so the condition you have described is certainly the most common.
Hope this is at least slight helpful hawk37.
O8