Help me understand my timing please

Rck you give me too much credit. I'm not really familiar with MSD stuff except in a general theory way.

To check rotor phase, it's not a "cool cap" LOL. All you need to do is get a hole in the cap anyway you can. Saw, heavy gunfire, drill, etc. Old caps are obviously preferred, why chop up a new cap? If "that thing" uses any kind of stander cap?? you might even score a used one from a buddy.

Generally, on a dist with vacuum advance, the rotor will be "as far" from one end (retard) of the cap contact as it is when the vacuum can is all in on the other end (advanced) but the rotor should still be at LEAST "corner to corner" from it's contact to the cap.

Mechanical advance should NOT change rotor phase except for maybe a tiny bit due to shaft wear, etc.

If you run an engine very long, as a few thousand miles, you can usually see rotor phase problems easily ---there will be short carbon tracks leading up to or from the cap contacts inside the cap.