I'm afraid who ever put together those Mallory instructions didn't fully understand the unit.

My timing experiments with the YH distributor where all done on the car, with high idle, not on a distributor machine. That's how I finally started to get hang of the relationships. So yes, especially with all the variables, its definately something that requires trials and adjustments.
Once you see where your at, if you don't like the slope, I can tell you what springs should get a steeper or shallower slope. We'll have to count the coils and if you have a caliper, measure the diameters and length the ones you have.