Your welcome John, ok I'll take a shot at trying to shed some more light on how the Advance System works maybe it will bring you some more understanding. These DS II Distribtors are a marvel of Enginering, combining several sub systems into one compact unit. I learned these concepts on building a mini bike around 7 or 8 years old had picked up an old Brigs & Stratton engine that i then overhauled, it had a simple point operated magneto ignistion and no means of advanceing the Ignistion timing, learned that this simple system was all you need to get an engine run. Next at 13 I bought my first car a 1928 Model A Ford that I did a complete restoration on, it had a very simple point and condenser type Distribtor with a hand lever operated advance system. With this system I learned how advancing the timing effected the engines power output you could feel the engines power change by advanceing or retarding the Distribtor timing with that hand lever.
Moving on next Ford developed the Load O Matic ignistion systems a simple advance system using the carb Venturi and engine manifold Vacuum to advance the ignistion timing by sensing the engines load. Next phase is Fords even more modern Distribtors with its new duel system of centrical and vaccum advance yet still using the old reliable points and condesor, these came out on the 1957 Y Block V8's giving greater power and very good economy this system was used until 1974. This brings us to the next advancement of the DuraSpark I & II Distribtors with their electronic trigger yet both still have the same advance system. This advance system that's basically performs automaticity after its set up and assembly, that's still based on those advance system parts that Ford first used back on 1957 V8's having many interchangeable parts between them. As you can see Ford kept building and modding their ignistion system, I think that's enough for the History to cover this.
Now when we are only looking at the advance systems individual parts many of which can perform several functions. So we have these main parts, the Distribtors center shaft togeather with its cam driven gear on the bottom to turn the shaft, this center shaft also has the ability to be adjusted into two different advance timing curves. Then there is the advance weights and the springs that control the advance timing. Looking at the advance weights we have a combo of a flyweight (or counter weight) which moves outward from the effects of the Centrical force acting on them, this is depending on the center shafts operating RPM which is 1/2 of the engines RPM. The second function of these advance weights is that they have a Cam shape to them that acts against the center shaft and thereby turning it more and advancing the ignistion timing. See the picture of showing how these advance weight will act on / advanceing the center shaft.
http://www.gofastforless.com/ignition/advance.jpg
Lastly are the springs that by their amount of tension act as some resistance as to how fast this timing advance comes into effect.
That brings us to the vacuum advance system that can also be tuned for better engine economy this system uses the engines manifold vacuum to add even more timing advance during times of higher engine vacuum. This higher engine vacuum ocures when the carburetor is at part throdle openings such as during any steady state driving, street, hyway, or freeway cruise speeds. Well there you have it hope that is of some help in understanding the advance systems. Best of luck in your tuning adventures.