Good work !
Really getting somewhere.
Most distributors that have 2 springs will have 3 angles to the 'curve'.
Considering curve A in your diagrams, the first steep part is the lighter primary spring, the lesser angle is the heavier secondary spring and the plateau is when it's reached maximum advance.
Curve B has a sing spring or 2 matched springs.
Curve A on both diagrams are the centrifugal advance. The two parallel lines are the minimum and maximum values so it allows +/- 2 degrees tolerance
Curve B is the vaccum advance.
For example I have here the 25D 41026 dizzy from my850 with two different springs. I always thought that it works like I draw it on the diagram below
20250209_185515 (1).jpg 33.86K
0 downloads
41026.jpg 79.92K
0 downloads