Initial timing
Steve,
Usually, Vacuum Advance is not "figured" in on Total Timing. Generally, we look for something around 34⁰ Total without vacuum advance. We set timing with vacuum advance disconnected. Most folks set Total and let Initial fall wherever it lands.
Initial + Mech = Total
Or
Total - Initial = Mech
I use a FBO limiting plate set to 10 and run an initial of 24 to give me a total of 34⁰
Once you got Total where you want it, plug in vacuum advance and cruise timing could reach 56⁰ with your vacuum can.
That's how I understand it.