Fr. John, I merged your question with a related topic. Not sure it's an exact fit, but let's see how it goes...
The "start here" setting for espresso depends on the particular blend, how much grounds you're using, the basket type, etc. As you found, the recommendations are somewhere around 1.5 numerical steps on the Macap dial.
No, the Macap doesn't have a notch like the Mazzer Mini:
I took the low tech solution and marked the dial and grinder face with a grease pencil.
Sure, but you'll disable a safety feature. It's to prevent someone from sticking their fingers (or other implement) in a running grinder. Yes, it happens.
They test at the factory, I think the evaluation model was in the low hundreds. I doubt it's used, 900 thwacks isn't as much as it sounds (no snide comments, please).